Palindrome Day 20200202 | Hacker News Reader

Palindrome Day 20200202

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723 pointsstanislavb173 comments

The nice thing about today's date, 2020-02-02, is that it is palindrome in three date formats: YYYYMMDD, DDMMYYYY, and MMDDYYYY.

This should probably be called "Universal Palindrome Day" because it is a palindrome irrespective of the endianness (big, little, or middle) that is used in various countries.

Here is the list of all such dates until the year 9999:

The next such one is over 101 years away from now.

Here is my own blog post on this topic: https://susam.in/blog/universal-palindrome-day/ :-)

So it happened like 900 yrs ago and after next one it almost take 900 yrs for same date to happen. And I am alive on one of this rare event. Need to cut Cake. :)

Not to sound corny but if you really think about it every single day is rare, just in different ways.

Reminds me of the interesting number paradox[1]. This can be easily extended to dates too in this manner:

Every date is interesting. Proof by contradiction: If there exists a non-empty set of uninteresting dates, there would be an earliest date in this set. But the earliest such date is itself interesting because it is the earliest uninteresting date, thus producing a contradiction.

[1]: https://en.wikipedia.org/wiki/Interesting_number_paradox

there has got to be a better objective method to define interesting numbers other than inclusion in a number sequence compendium.

perhaps if we hypothesize that there are a (countably) infinite number of number theoretic theorems, might every number be either a unique case or the largest or the smallest example of some instance?

There is no largest or smallest real number. Therefore a set without a largest or smallest member is not necessarily empty.

Alternatively, being the smallest in the set of uninteresting numbers does not make a number interesting, at best it is unique like every other number and therefore uninteresting.

Not true of dates though, since you can set hard bounds at the big bang (or whatever) and the heat death of the universe.

So the universe creates time?

Yes. After the heat death, nothing will ever move or change and so it the universe will remain in a frozen state. Time will have stopped.

Sine time is relative based on the observer and observed, if neither change in any way (no “work” happened and no information is exchanged, even on the level of fundamental particles (or fields/loops/strings or whatever happens to be at the bottom)), for every possible combination of observer and observer, then time has not advanced in any meaningful sense.

You don't need both bounds anyway. A countable set without a lower bound in any representation is already a paradox.

> There is no largest or smallest real number.

The interesting number paradox applies to natural numbers, not real numbers.

> Alternatively, being the smallest in the set of uninteresting numbers does not make a number interesting

You are taking this too seriously. :-) Everyone would agree that "interesting" is subjective. This is supposed to be a humorous paradox, not a mathematical fact!

That was meant to be humorous, however dates are not natural numbers.

It is obvious that dates are not natural numbers. What is your point?

A set of dates obviously has an earliest date. The humour here is that an earliest date within the set of uninteresting dates is itself an interesting date by virtue of being the earliest such date in that set.

> A set of dates obviously has an earliest date.

Uhh, no you’re thinking in terms of a finite set. From the set of all dates, what’s the latest possible date, or conversely the earliest possible date. The temptation is to say infinite BC is the earliest possible date, but infinity is not a number.

But there is no infinite BC, right? There cannot be any date earlier than the date of the big bang. That establishes a lower bound for the set of dates, does it not?

The Big Bang is an apparent discontinuity, but we have no idea if a universe existed before this one. Alternatively, multiple universes could exist and those alternate universes could be much older. So at least theoretically things much older than our universe could exist.

> infinity is not a number

Infinity is not a number, it's a set of numbers, but specific infinities (e.g., the cardinality of the natural numbers, aleph-naught) are individual numbers, just not finite numbers.

Yes. I know. I Know. But you can't cut cake everyday. Need to make up some reason.

I love the term "middle endianness" and how clearly it highlights how nuts the American date notation is.

EDIT: fwiw, in my native language, most numbers from 100 and 1000 are pronounced middle endian, so I'm not complaining.

The American date notation is simply a direct reflection of the spoken language. We say "February second, 2020" and we write "2/2/2020". (Contra the root comment, I can't agree that 2/2/2020 is a palindrome.) I don't see this as being crazy or even unusual.

When order matters, you invariably want big-endian notation, which is why that notation is acceptable everywhere regardless of the usual native notation. But by the same token, it means that all other styles are equally "nuts". European day-month-year notation doesn't have any technical advantages over month-day-year.

> We say "February second, 2020" ...

Interesting. We (Australian) say "Second of Feb, 2020". ;)

Spanish is "Dos de Febrero de 2020"

In Dutch we say "2 februari 2020". So littleendian is perfectly natural for us.

What about the Fourth of July then?

What about it? It's the name of a holiday.

12/25 is often called Christmas, and yet 9/29 is never called Michaelmas. Same thing.

The parent was making the point that generally Americans refer to dates such as "May 2nd", "April 14th".

But one of their biggest holidays is explicitly called "4th of July", changing the ordering.

And a proper name is not good evidence of normal usage. "Christmas" is normal use in an older, Catholic method of identifying calendar dates. Americans don't use that method; most couldn't if they wanted to. But Christmas itself is still identified that way for historical reasons -- the word has gone from being an example of talking about the calendar to being an example of a proper name.

"4th of July" is not a method that Americans couldn't use if they wanted to, but it is an ossified usage that doesn't reflect how Americans generally refer to dates. Like Christmas, it is a proper name of limited evidentiary value.

Huh, where I'm from the 24th of December is Christmas. The 25th is the day after Christmas.

Really? Where are you from?

This might help explain how Santa delivers all those presents in "one night".

Possibly it's the difference between being an atheist and a catholic, since I faintly remember my catholic friends receiving presents on the morning of the 25th, while I would receive them on the evening of the 24th.

Interesting. Are you from Canada?

I'm from Europe, but not from an English speaking country.

Opening presents on Christmas Eve is a pretty common tradition.

Calling Christmas Eve "Christmas" is not common at all.

I don’t know, I always imagined that you said “4th of July” because up to that point you were Brits and that’s how we say it.

...and then the very next day, without adult supervision, you started saying your dates weirdly and dropping the “u”s out of words, stuff like that.*

* DISCLAIMER: May not be an accurate representation of history. :P

It's more accurate than it might sound. If I recall correctly, the American spelling reforms were largely a one-man top-down effort driven by the ideological goal of being more separate from Britain.

It's commonly referred to as "Simplified English" for good reason. ;)

> I always imagined that you said “4th of July” because up to that point you were Brits

True, but nowadays we say "Independence Day" :-)

Macy’s call it 4th of July

https://www.macys.com/shop/4th-of-july-sale

You can say any date like that in American English, it’s just less common. “Today is the second of February” sounds perfectly natural, but I’d be more likely to say “Today is February second”.

As in everything else in American English, there are exceptions.

That middle-endianness is spoken doesn’t make it better. It’s still crazy.

Starting with the most general and ending with the most specific is a logical order. Doing it the other way round is also logical. But starting with the middle makes no sense.

It doesn’t seem unusual to you because you use it often.

That said I’m German and I realize that German postal addresses are crazy for the same reason. I wish we‘d adopt the Chinese format: country first then province (state), then County then town then neighborhood then street and house.

German addresses are middle endian: street then house number then zip code then city then country. The right order seems to be: city, zip, street, house number. Most general to most specific.

For something like addresses, usage pattern is going to matter... if most mail is sent within the city, then putting street first makes sense, because the city is almost always the same; it shouldn't take up valuable real estate at the front of the address.

The broadest unit that is likely to change going first makes sense.

Or from botton to top: country, city, zip, housenumber, street, name.

What's so crazy about the German notation? Seems to make perfect sense, as it goes line-by-line from the smallest to the largest sorting unit:

1. Exact street location (street + house)

2. District (postal code)

3. City

4. Country

Also I prefer this order over the Chinese, because I assume most people handling mail will need to smallest details and it would just be very annoying if local mailmen had to skip over country and city names every time before reaching the bit they actually need.

I think he meant, that the street name is before the house number

You listed two details on one line to make the German notation seem non-crazy.

A more "logical" notation, as per the gp's comment would start:

1. Exact street location (house + street)

In Poland We do it exactly as you said:

Street_name street_number/house_number

Postal_code, City, Country

The typical English-influenced way to do it starts with the number,the most specific thing.

  10 Downing Street
  London
  SW1A 2AA

(The postcode is least-specific first: SW is South West London, 1 is the district nearest Central London, and the 2 would usually be a few streets and the AA 5-10 houses, but this is a unique code for an address that gets a lot of post.)

Funnily enough, with the addition of the newest element to that format — the postcode — to the end, this format also becomes less "logical", postcode being very specific.

Of course that's arguable, as postcode shouldn't really be considered a component of-, rather an alternative to- other sections of the address.

A postcode (or local equivalent) isn't necessarily particularly specific. For example, here in Austria the equivalent of a postcode might cover a whole city district.

Yes, similar to the US. But British post codes (or at least the ones I’ve seen in London) are in fact very specific.

Indeed, a single postcode in the UK will contain (on average) about 20 addresses and (usually) only refer to a single street.

ZIP+4 in the US is quite specific, though. E.g., my ZIP code is probably > 50k people but the ZIP+4 is just my apartment building.

The house number is smaller than the street, but the street comes first. If we put the house number first, then we'd get a logical order.

You're thinking of street and house number as two things. Germans don't. Or at least I don't. Your approach makes as much sense as picking movie titles with numbers at the end apart into two things.

Street and house number are certainly two different things. It's more like series of movies (Die Hard 1, Die Hard 2, etc. are different movies but part of the same series. In the same way, a street could be seen as a series of houses or addresses. So the smallest unit is the house, then the street.

Yes, it's like a movie series. It's Die Hard 2. That's one name, not two, "2" and "Die Hard", but one: "Die Hard 2".

I didn't say it was two names, I said there are two different movies within the Die Hard series. Just like two different houses on the same street.

Yes, but each movie is a single entity and the number is part of that entity. Just like with "street+house number". It's one entity, not two.

You are missing the name of the house resident as the first line. Once I had my mail returned to the sender because my parents-in-law did not put our name on the envelope.

Hungarian addresses are (or were) worse. According to http://www.columbia.edu/~fdc/postal/, it's:

1. name of recipient, 2. town name, 3. street address or post box number, 4. four digit postal code.

(I have a vague memory of seeing that sort of order in German, too, in a historical context, but perhaps it was from Austria-Hungary.)

> That middle-endianness is spoken doesn’t make it better. It’s still crazy.

The english language—and every other real-world spoken language—is full of rules and exceptions that make absolutely zero logical sense. How far down this road do you want to go?

As long as we speak in a specific order, I don't think it's crazy at all to write in that same order. After all, normal written sentences follow the spoken order of words, too.

Chicken and egg. I (in British English) say the second of February.

I would agree that there's influence in both directions between the written pattern and the usual manner of speech. All I'm saying here is that there's nothing surprising about the written pattern matching the usual manner of speech. That is the primary purpose of writing; it's weirder for the writing not to match the speech. (Although certainly not unheard of; it is the norm in e.g. Chinese.)

Unfortunately, you're using an idiosyncratic American "usual manner of speech" to justify an idiosyncratic American format.

And the problem with that is... what? Are you saying we should all speak Chinese because spoken Chinese dates go in correct sorting order?

Idiosyncratic? Of course. People in different countries speak differently. Every natural language is totally arbitrary and “idiosyncratic”. What is your point?

The assertion that most people and most countries in spoken language say “day [of] month”, which I find anecdotally accurate, although that’s mainly in European countries and languages

This matches why almost every country in the world uses “d/m/y” in normal usage.

If you were aware of the mind-boggling diversity of human language you would not make claims like “typical languages do X so one that doesn’t is idiosyncratic” (unless backed by serious research spanning the thousands of known languages). You would also not think experience with a few languages from the Indo-European family is generalizable.

Standard Chinese for example uses Y/M/D and I’m sure you can find many examples of other formats.

I think the only major language using the M, D, Y spoken order are American-influenced English and Ewe (Ghana etc).

Several countries write a short data as M/D/Y, but these mostly have a significant American influence.

The claim was "almost every country in the world uses d/m/y in normal usage", which doesn't pass the laugh test.

It wasn't "almost every country in the world doesn't use m/d/y", even if you would have liked it to be.

British English? Which part of the UK is that from.

I speak English English.

Little endian notation is somewhat mixed endian itself, because it contains 3 numbers, each number by itself is big endian, but the 3 numbers are arranged in little endian fashion amongst each other.

D/m/y is little endian. In a base 10,000 system there would be 3 symbols, each unique.

Sure, but humans would have a hard time memorizing 10,000 symbols.

If each unique symbol for a number was made up of smaller symbols arranged using a simple algorithm you wouldn't necessarily need to memorize them all. Kind of like Roman numerals, but much a bit more complex.

I don't have to remember the exact symbol for 2,020 in Roman numerals, because I can figure it out. In fact, I have no idea what it would be without sitting down and doing so.

I'm not saying it would be a good system, but it could be usable by mere mortals. I guess you could debate if this would really be "10,000 unique symbols" or just something akin to our current writing system for numbers.

Just as with inches, feet, and pounds the system works better in practical real world conversation than it does in more formal language.

“When’s your birthday? 10/23. When are we going to Ma’s? 11/19 thru 11/29. When do you go back into therapy? 12/8.”

“When’s your birthday? 23/10. When are we going to Mum’s? 19-29/11. When do you go back into therapy? 8/12.”

As it could be written in English in Britain, Australia etc.

23/10 is pronounced "23rd of October" or (usually) "23rd'f October" or "23rd'f the 10th".

The range is "19th to 29th of November" or "... of the 11th".

The pronunciation "second of the second twenty-twenty" is usually used when the listener is writing, typing or confirming the date in figures.

It doesn't "work better" than any other system, you're just more used to it.

i think this especially goes for the English system vs metric measurements (though confusingly the English do not use the Imperial system, officially at least) Our brains are much better wired for binary systems like bushels and pecks rather than the French derived decimal system which is only good for studious things (like science) where you have of many orders of magnitude to keep track of regularly. Much easier to communicate/grasp half than 5/10ths.

Similarly the Sexagesimal notation, in common use (clocks etc), points to an generalization that would have been much better than the French system, where we rely on primes for increasing places in the number. Eg 4321(primal) would be 4x5 + 3x3 + 2x2 +1x1 = 34(decimal). Historically we may be stuck with counting on our fingers and toes though, through eternity.

The more "logical" Metric system which is not an extension of the "practical" Imperial system is inevitably bastardized and Creoled in everyday usage. Eg one buys a "Pound Plus" of Chocolate from Trader Joe's (500 grams!). Why is the choice is not one (or fice) Hectogram(s) vs one Kilogram i do not know... except that Hectogram is so obtuse/abstruse i had to google it! Maybe someone in a Metric country can correct me, if they think i am wrong using words like abstruse. One inevitably finds doubling and halving in everyday commerce.

We would do a lot better to extend to tripling, quintupling etc, like the Babylonians did, than directly to the (insane, in my opinion :-) French 10x Metric system.

Not that i am an American chauvinist. Eg i think the American middle endianistic dating system is off the wall weird, and i go out of my way to circumvent it.

Does you native language also have gendered numbers? Is there gender parity with odd numbers male and even numbers female? Or does it enforce the numeric patriarchy by gendering prime numbers male and composite numbers female?

https://insight.kellogg.northwestern.edu/article/are_numbers...

https://www.livescience.com/15859-odd-numbers-male-female.ht...

Out of curiosity, what's your native language?

Dutch.

Afaik all Germanic languages except English¹ (and close relatives) have the same thing. Ie this stuff is the same in Dutch, German, Swedish, Danish², etc.

We don't say "Twenty-three" but "Three-and-twenty". So far so good, but we do the hundreds, thousands etc just like English does. Thus, 123 is pronounced "hundred-three-and-twenty", i.e. precisely as nuts as what Americans do with dates.

¹) I assume that English fixed this at some point along the way (maybe due to French influences?), because the special number names between 10 and 20 do follow continental Germanic rules, eg compare "sixteen" and "twenty-one". We mainland Europeans like to mock the English speaking world for their insane unit systems, but at least their numbers make sense.

²) Danish has it worse. They have the same insane number ordering plus insane number names.

3 is "tre", 30 is "tredive". 4 is "fire", 40 is "fyrre". So far so good. Like in many languages, 10x sounds a bit like x.

But 6 is "seks", and 60 is "treds" (!). To make matters worse, 5 is "fem" but 50 is.. "halvtreds" (!!). Similarly 9 is "ni" and 90 is "halvfems". In Danish, for x <= 5 < 10, 10x sounds like ["", "halv"][x mod 2] + ceil(x / 20). I tried mocking the language by saying "fems" instead of "hundrede" but I just got blank stares.

And I'm lucky enough to have grown up on the same insane middle endianness as the Danes. I can't imagine how impossible Danish numbers must be to learn for eg an English speaker. Every time my wife says a number in Danish I spend half a minute doing the math, "she said something with 'tre' in it, so threes, but it ended with an s, so three times twenty, oh but wait there was 'halv' in front of it so subtract 10, ah, fifty". But she didn't say that, she said "to-hundrede-tre-og-halvtreds". By the time I'm done with the math I already forgot the other digits :-)

(And you didn't even mention how "tredive" is pronounced.)

Swedish and Norwegian (and English for that matter) used to count the Germanic way, but swapped to the modern way for 20 onwards at various points.

There's an English nursery rhyme "Four and Twenty Blackbirds" which has the old way as its title. English also used to use the vigesimal system. My great-grandfather was supposedly a bit of a traditionalist even amongst his rural friends, who poked fun at him for saying things like "two score nine? I'm not paying that!".

> how clearly it highlights how nuts the American date notation is

Middle Endian dates make sense when the season something happens in is important.

Also they contain only two distinct digits, rest mostly have 3 or more different digits.

Yeah, we won’t get a two-digit universal palindrome for a long time (12-12-2121).

Yes, a YYYY-MM-DD format palindrome date that is also a palindrome in DD-MM-YYYY and MM-DD-YYYY formats cannot have more than two distinct digits.

Let us represent the 8 digits of such a date (in YYYY-MM-DD format) as abcd-ef-gh.

Since abcd-ef-gh (i.e., YYYY-MM-DD format) is a palindrome, we get a = h, b = g, c = f, and d = e.

Since ef-gh-abcd (i.e., MM-DD-YYYY format) is a palindrome, we get a = h, b = g, c = f, and d = e.

Since gh-ef-abcd (i.e., DD-MM-YYYY format) is a palindrome, we get a = f, b = e, c = h, and d = g.

Combining all of these, we get a = c = f = h and b = d = e = g.

Therefore, such a date must be of the format abab-ba-ba, i.e., it may have a maximum of only two distinct digits.

From another comment on this thread

> 20300302, 20400402, etc

https://news.ycombinator.com/item?id=22214936

They are not universally palindromic.

For example, 2030-03-02 (yyyy-mm-dd) when written as 02-03-2030 (dd-mm-yyyy) is not a palindrome.

All dates in the list I have provided are universally palandromic, i.e., they are palindromes irrespective of the endianness (big, little, or middle) used to represent them.

Where is 2021-12-02 though?

edit: NVM. Should read better.

2021-12-02 (yyyy-mm-dd) is not a palindrome when written as 02-12-2021 (dd-mm-yyyy).

The list in my comment contains only those dates that are palindromes in all of these three formats: yyyy-mm-dd, dd-mm-yyyy, and mm-dd-yyyy.

I hope this is pointed out to kids in classrooms all over the world. Growing up I remember my teachers would point out these cute number tricks/events which contributed to piquing my interest in math and numbers, and eventually engineering.

> I hope this is pointed out to kids in classrooms all over the world.

For at least some of them it’s the summer holidays and they are heat addled and doing something completely mindless with no idea of the day or date. I’m rather jealous.

Also, it's Sunday.

Superbowl* Sunday

Where I live the year isn't 2020. So, meh.

My high school math tutor's cute thing to point out was that for asymptotic functions like the graph of y = 1/x [1], since the universe is spherical, the asymtotes will travel off the page in a straight line around the universe and eventually meet, coming back onto the graph in another quadrant from the other direction, so in fact it is one single connected line.

I went into engineering and not physics, and never learned enough of the latter to question whether he was serious. Furthermore, since this was the first time any math tutor of mine in 18yrs had ever related anything to the real world, it seemed like magic to me and so I still ignorantly tell people it to this day.

[1] https://www.wolframalpha.com/input/?i=Y%3D+1%2Fx

My maths teacher for much of secondary school, who was the "pure maths" teacher when we were old enough for that to be taught separately, started one year with an elaborate 4-colour drawing of a steam locomotive on the whiteboard. There was no explanation or further reference to it in that lesson.

As we learnt trigonometry, he'd sometimes draw just part of the scene, and explain how it related to what we were learning.

I remember the coupling rods: as the locomotive moves, each end traces a sine curve: https://en.wikipedia.org/wiki/Coupling_rod

And also the electric catenary, which has a hyperbolic cosine curve: https://en.wikipedia.org/wiki/Overhead_line

I think there were also the pistons on the steam locomotive, and the curvature of the track.

(Occasionally, it was like the intro to https://vimeo.com/77451201 )

Also: it’s day 33 (palindrome) of the year and we have 333 (palindrome) days left.

02/02/2020 is the most palindromic date ever.

https://youtu.be/4fE_sXZjxng

Not only that, but it's a strobogrammatic number when viewed on a 7-segment display.

What is "most palindromic"? Wouldn't 11/11/1111 be the "most"?

The video notes that it is also the 33rd day of the year and 333 days remain. Thus another palindromical event.

I would argue that your example is tautological and therefore less significant.

It's finally the year of the DECSYSTEM-2020! It was so far ahead of its time.

https://en.wikipedia.org/wiki/DECSYSTEM-20

And it’s my birthday. I always joked that my birthday was US-proof (I’m not American), but this year it’s extra-special.

A happy birthday to you!

Today is my son's due date! I've been hoping for months that he'll be here on time for this palindromic birthday, but nothing yet...

Eh man, can’t do much about these things. I was born on 02/02, married on 05/05, first child on 07/07, but the second child “broke the chain” with a 21/11... ️

happy birthday!

Hey, happy birthday!!

Today was my wife's due date. The baby came 10 days early though. It's been a great experience!

There’s also coming up: 02/02/2020 02:02:20.20

I might have to stay awake for this.

For us located in EU it’s at 20:20:02:02 in the evening :-)

Depending on how you write your dates, 20211202 is the next one.

And, if you write your dates that way, what will the one after that be? 30100103?

In a thousand years, we might be on yet another calendar system.

https://en.wikipedia.org/wiki/List_of_calendars

I think we already are using another calendar system! Most used dates in existence are probably using Unix time, at least I know I only check the calendar a few times a day but I have systems running checking it multiple times per second.

What about 20300302, 20400402, etc?

facepalm Yes.

Isn't that the next one regardless, just when it is depends on how you write dates?

you can write dates however you want to, it's just a made up notation. It would not be difficult to come up with way of writing dates which is almost always a palindrome.

For once, I found out about this early in the morning instead of the day after.

For those in the US, also groundhog day and superbowl sunday (american football championship).

And also my birthday!

Mine also! Having a palindrome / groundhog / birthday / super bowl party tomorrow!

Tomorrow may also be groundhog day.

> superbowl sunday (american football championship).

And for many it's "watch a bunch of ads with budgets in the $5-10+ million range" day.

https://fivethirtyeight.com/features/how-much-football-is-ev...

It's also my 21st birthday! So close.

Happy birthday! Same for me, although my years are almost exactly twice yours.

I remember where I was at 8.02 pm (2002) on 02/02/2002 - on the phone to my mum, who was in a different timezone so couldn’t enjoy that palindromic minute.

Sadly I slept through 0202 this morning...

FTA:

> Because of the Gregorian Calendar Reform of 1582, the numbers of days after 1001-01-01 are fictitious, strictly spoken. They are valid only then, if we adopt the reform for dates before 1582, subsequently.

The explanation is muddled. This concept has a name, the definition at WP is succinct and clear: http://enwp.org/Proleptic_calendar

for those who slept in, 05.05.2020 is coming soon... the mirrored day...

This post would not be complete without The Ballad of Palindrome by Riders In The Sky:

https://www.youtube.com/watch?v=xzvQEstC03o

A Spaghetti Western style story, starring your hero, Palindrome.

Don't forget Bob, by Weird Al Yankovic:

https://www.youtube.com/watch?v=gAfIikFnvuI

How would this be a Spaghetti Western rather than just an American Western?

In some quarters, “spaghetti” has just become a derogative term meaning “low quality”. Sadly, the concept that “spaghetti western” was actually a genre with certain characteristics but containing a number of masterpieces, was lost under the wave of poor clones of The Good, The Bad and The Ugly.

You're right, it was the wrong term.

Project Euler palindrome problem.

https://projecteuler.net/problem=4

There will be lots of palindromes coming up:20211202,22200222,21211212,22011022,22211222...

There is also the 20th of February.

20200220 yy/mm/dd

02202020 mm/dd/yy

20022020 dd/mm/yy

02-02-2020 also work (02022020)

Happy birthday to me!

The Human Palindrome will be born tomorrow and die on 2121-12-12 at the age of 101. And in true palindromic fashion, his life will start and end with diapers.

Fun, clever, and witty comments are increasingly rare here on YC. Thank you for this.

Any responsible parent will call him Bob or Anna, of course. Taking surnames into account is going to be a bit harder.

Here's a good resource for anyone becoming a parent today: https://parentinghealthybabies.com/palindrome-names/

Oof, that list is terrible. Natan is listed twice, and there’s at least one name that isn’t a palindrome. The only two names that really work from that list is Anna and Hannah. Nobody should name their kid Bob in 2020, it’s not a «young» name yet. Thr older Bobs need to die off before it’s an acceptable kid’s name.

As for the rest of those names, I refuse to acknowledge them as names. They’re more like onomatopoeia.

Are you saying “Ada Lovelace” had a fake name? :)

Ada, Ava, Eve and Viv are all names I’ve seen in the wild and would consider reasonable names too. There’s also nothing wrong with Bob, despite what you seem to think. So together with Anna and Hannah, that’s 7 names.

They’re names, but like Bob, they’re not names that fit kids. Names are like fashion, they come in cycles. If your name is off-cycle, it’ll often sound a generation or two too far removed.

All of you are just talking about American name fashions. The point of 20200202 is that it's a palindrome in every single country and culture that uses AD and the Gregorian calendar. Many of these names may be very suitable in other cultures.

One of the names in that list should be Aziza, instead of Azia. It means dear or precious in Arabic.

Mike Kim, Able Elba (perhaps related to actor Idris), Renee Keener, or Lia Vail. Source:

https://www.quora.com/What-are-some-first-name-last-name-com...

Edit! One I just thought of while brushing my teeth:

Errol Lorre (perhaps related to Peter?)

Someone like Bob Anna or Anna Bob

s/will call him/will have called him/

Only way to be sure is to name all 360,000 of them palindromically...

Their name will be otto

Note that there are ~360,000 babies born everyday.

On average today, 70% of Americans live to the age of 65. That rate varies greatly from country to country, but let’s assume that due to improvements in medical science and wealth, the likelihood of anyone born today, worldwide, being 50%.

After that, it’s a bit tougher. But today, the likelihood of a person aged 65 reaching the age of 100 is 3%. I couldn’t find data on the odds of 101, but let’s assume that this percentage will also be 3% in the future.

This means that there are approximately 5400 babies born today, that should reach 101. So almost certainly there is someone who will qualify as a Human Palindrome?

As mentioned, there are only two of these special 101 year gaps, in the 10,000 years from 0 to 10,000. Almost certainly there were no cases of this from 1000 to 1100?

So some baby born today will almost certainly become a trivia question answer for hundreds (thousands?) of years to come? Based on nothing more than the day they were born.

There are quite a few life tables, vide https://www.ssa.gov/oact/STATS/table4c6.html.

It seems that roughly for 360k babies there should be 1 man and 8 women dying at that age (death rate is ~60% per year). Of course, assuming US death rates, and technology as of today. Given that most kids are being born in poorer regions, and that global warming my seriously affect life span (especially in these regions), the results may be significantly lower.

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