What number comes next? The On-line Encyclopedia of Integer Sequences knows | Hacker News Reader

What number comes next? The On-line Encyclopedia of Integer Sequences knows

nytimes.com

92 pointswglb37 comments

http://web.archive.org/web/20230523222110/https://www.nytime...

I think the Neil Sloane Numberphile episodes are amongst my favourites (along with Cliff Stoll of course) and it's amazing that such a hobby project can become so useful. I think the appeal of his videos is that he introduces sequences as a type of game, draws you in and then later on, the interesting questions are introduced.

Another comment in this thread mentioned that Neil Sloane now has his own channel, and is making some videos [0]. Very fun from that 20 minutes I've watched so far.

[0] https://www.youtube.com/watch?v=9ogbsh8KuEM

The following are real examples of submissions that were rejected:

A-numbers of sequences contributed by [your name] (however, this might be appropriate on your OEIS Wiki user page).

Experience points required for a Pokemon in the "erratic" experience group to be of level n.

The year 10^n decimal digits of pi were first computed (Not well-defined!)

Primes of the form n^3 + 2 n^2 + 37 n + 73.

Non-trivial circulation in decreasing order: numbers of the form lim_{x->+inf}(a[x]b) with b<>1.

You start at the number 1 and you add 2 until you get to the 4th number in the sequence, in which you then add the 1st and 3rd number of the sequence, which will give you 6. Then you do the same thing, adding 2 to each sequence, but for every 4th number you add the 1st and 3rd number before it.

Consecutive Quotients minus a third term x(k) = fix(ax(k-1)/x(k-2))-bx(k-3).

Prime numbers of the form 1 plus n x 10@r (@ means "to the power of") where n is an integer between 1 and 9 inclusive, and r is an integer greater than or equal to 0.

Concatenate a semiprime with a Fibonacci number to obtain a palindrome with at least two distinct digits.

The sequence 1,2,3 (and no further terms are known). The sequence 2,4,6 (and no further terms are known).

From https://oeis.org/wiki/Examples_of_what_not_to_submit

> Concatenate a semiprime with a Fibonacci number to obtain a palindrome with at least two distinct digits.

For some reason, the thought that someone worked on this makes me very happy :)

I've solved many combinorica-ish problems by extracting a sequence from a numeric solution and then using OEIS to find generating formulas then figuring out which one was the right one.

interesting because in my experience Chat GPT has severe problems "understanding" OEIS so i wonder if it could solve the problems the way you did?

Past discussion : https://news.ycombinator.com/item?id=26848517

Am I right in remembering that at one point the OEIS ran on a single machine that Neil Sloane ran himself?

Personally, I used to use the database for counts of graphs (labelled vs unlablelled) and chemicals. Very useful and clear single-purpose tool.

Does anyone know how it compares to the Cinco Encyclopedia of Numbers? Anyone have a recommendation for someone who might be new to numbers?

https://youtu.be/rVtHrgdcvZA

cinco is a great resource, I'm on volume CCLXXIX and I'm still finding new numbers I've never even heard of like 2,737,829,283

I just got into the 30,000,000 range. Literally riveting.

I keep on meaning to finish a redesign of the oeis site that I started a few months ago[0]. I've only spent a day on it so far, but I'm hoping it makes the site far more approachable to new comers.

[0] https://oeis.femto.dev/

I really like what you did, great work! Please post it whenever you feel it's ready. I'd love to see the code too.

Source code is available here[0]. Permissively licensed under MIT.

[0] https://github.com/popey456963/pretty-oeis

I love this! You should continue!

Some feedback: it lacks a search button. I mean, you can type a sequence, but have to hit the enter key to search. I'd expect at least some mouse-pressable button to be there that searches too (either the magnifying glass that's already there, or a button labeled "search").

You may say that "it's good enough you can press enter", however the site starts out already showing you the digit sequence "1, 2, 3, 6, 11" so you don't need the keyboard, but no way to actually search for it using only the mouse.

Second feedback: it shows icons that look like a maple leaf in the top right without any explanation what it means, perhaps a tooltip could show what this maple leaf means? Idem for the other icons there.

Third feedback: you have to individually click a full expand and then in addition expand all the subsections to view them... at least a dedicated page to entries should show everything immediately.

Final most important feedback: it doesn't have individual URL's to the sequences anymore! That seems an important missing feature. It only shows results in ephemeral rendered boxes on the main page, no way to link to an individual entry! Clicking an entry should open its individual page. Middle mouse clicking should open it in a new tab like a real link does.

This was incredible feedback, thanks so much for taking the time to write it out. I've implemented 2, 3 and 4. You can now directly link to pages[0] and it'll auto-expand all boxes. The icons are intended to show whether the sequence has a code submission attached. There's now a popover attached to them to explain this.

1 will take some design work, and I've only got an hour or so to work on it now. I definitely agree however that a 'submit' button on a search is essential.

[0] https://oeis.femto.dev/A000045

Wow thanks for implementing all those improvements!

Shout out to my favorite integer sequence, The Recaman Numbers:

https://www.youtube.com/watch?v=FGC5TdIiT9U

... which is https://oeis.org/A005132 ...

"and not already in the sequence" --> bound to be weirdness in that.

What to do if I've come up with an easily explainable number sequence that's not defined in the OEIS? It's a simple algorithm that's easy to perform with a deck of cards

There are an infinity of possible sequences you could write down. The ones in OEIS are ones where there's relevance to it in terms of other sequences or other mathematical ideas that make them useful to describe.

You submit it to OEIS and it may be added.

https://oeis.org/Submit.html

Paywalled article, but I’m assuming it’s talking about the OEIS located here [0]. Such a cool resource, especially if you are trying to calculate S-boxes[1], or a lot of digits of an irrational number, or Bernoulli numbers or something. The links section for each sequence is super useful for initial research.

[0] https://oeis.org [1] https://oeis.org/A354500

Related. Others?

Loda-lang – language, computational model, and OEIS miner - https://news.ycombinator.com/item?id=28639932 - Sept 2021 (14 comments)

The Connoisseur of Number Sequences (2015) - https://news.ycombinator.com/item?id=27074978 - May 2021 (2 comments)

The On-Line Encyclopedia of Integer Sequences - https://news.ycombinator.com/item?id=26848517 - April 2021 (31 comments)

The On-Line Encyclopedia of Integer Sequences - https://news.ycombinator.com/item?id=21366618 - Oct 2019 (28 comments)

Easter Egg in OEIS: Fur Elise in MIDI - https://news.ycombinator.com/item?id=20475896 - July 2019 (1 comment)

The online encyclopaedia of integer sequences - https://news.ycombinator.com/item?id=18524115 - Nov 2018 (3 comments)

2, 3, 5,? Bell Labs (1968) [pdf] - https://news.ycombinator.com/item?id=18357229 - Nov 2018 (4 comments)

The On-Line Encyclopedia of Integer Sequences [pdf] - https://news.ycombinator.com/item?id=18015493 - Sept 2018 (4 comments)

OEIS submissions - https://news.ycombinator.com/item?id=17477542 - July 2018 (1 comment)

The On-Line Encyclopedia of Integer Sequences - https://news.ycombinator.com/item?id=15900294 - Dec 2017 (1 comment)

Pictures from the On-Line Encyclopedia of Integer Sequences - https://news.ycombinator.com/item?id=11711212 - May 2016 (5 comments)

Play a Sequence - https://news.ycombinator.com/item?id=10445865 - Oct 2015 (3 comments)

The Surprising Power of Neil Sloane’s Encyclopedia of Integer Sequences - https://news.ycombinator.com/item?id=10435690 - Oct 2015 (7 comments)

An Interview with OEIS's Neil Sloane - https://news.ycombinator.com/item?id=10153589 - Sept 2015 (1 comment)

The Connoisseur of Number Sequences - https://news.ycombinator.com/item?id=10045818 - Aug 2015 (1 comment)

The Connoisseur of Number Sequences - https://news.ycombinator.com/item?id=10020831 - Aug 2015 (1 comment)

The On-Line Encyclopedia of Integer Sequences - https://news.ycombinator.com/item?id=9919535 - July 2015 (19 comments)

Neil Sloane: the man who loved only integer sequences - https://news.ycombinator.com/item?id=9380292 - April 2015 (2 comments)

* The On-Line Encyclopedia of Integer Sequences* - https://news.ycombinator.com/item?id=6650490 - Oct 2013 (20 comments)

The On-Line Encyclopedia of Integer Sequences - https://news.ycombinator.com/item?id=2496629 - April 2011 (7 comments)

The On-Line Encyclopedia of Integer Sequences - https://news.ycombinator.com/item?id=888577 - Oct 2009 (2 comments)

I used to use the oeis when I was doing research in theoretical physics a few years back. I hadn't actually seen Neil Sloane before, I only knew his name from the website. I just watched some videos of him, he is really wonderful

Well, does the Encyclopedia knows what comes after 1,2,4,8,16? Hint: if you follow the Mathologer, you would know that there is a number different from 32…

There are some non-32 hits if you search for this prefix. https://oeis.org/search?q=1%2C2%2C4%2C8%2C16&language=englis...

For a sequence of n numbers, fit an n-1 degree polynomial on (0, v_0), (1, v_1), ..., and compute for n. Doesn't even have to a polynomial. Any independent function base will do, I suppose. And who can contradict you?

Doesn't really matter what "mathologer" thinks the next number is.

The most important number sequence is of course in there.

Simply search for 8,6,7,5 and you should find it.

There are 176 sequences that match 8,6,7,5. Which one did you mean?

Anybody here who posted submission and received "less" tag?

That analogy about the FBI fingerprint database is one of the most tortured metaphors I've ever heard.

I thought it was pretty good. You can solve a (mathematical/forensic) mystery by searching a database for information collected long ago, that relates to information you obtained just recently.

The FBI would like to remind you that officially it's a "waterboarded" metaphor.

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