A calendar of the upcoming 100M anniversaries:

    $ for x in {15..21}
    > do
    > printf '%2d %s\n' $x "$(
    >   env TZ=UTC date -d "@$(($x*100000000))"
    > )"; done
    15 Fri 14 Jul 02:40:00 UTC 2017
    16 Sun 13 Sep 12:26:40 UTC 2020
    17 Tue 14 Nov 22:13:20 UTC 2023
    18 Fri 15 Jan 08:00:00 UTC 2027
    19 Sun 17 Mar 17:46:40 UTC 2030
    20 Wed 18 May 03:33:20 UTC 2033
    21 Fri 18 Jul 13:20:00 UTC 2036

It's neat how they seem to roll around every pi years.

    >>> 1e8 / (3600 * 24 * 365.25)
    3.168808781402895
    >>> math.pi
    3.141592653589793