[seqfan] Re: How many numbers have n letters?

[Neil Sloane]

Hans, Thanks for mentioning A121064.  I've cloned it as A362449 to get a
"positive numbers" version to match the GCHQ puzzle.

Best regards
Neil

Neil J. A. Sloane, Chairman, OEIS Foundation.
Also Visiting Scientist, Math. Dept., Rutgers University,
Email: njasloane at gmail.com



On Sun, Apr 23, 2023 at 12:24 PM Hans Havermann <gladhobo at bell.net> wrote:

> I remember working on one of these: https://oeis.org/A121064
>
> > On Apr 22, 2023, at 11:24 PM, Neil Sloane <njasloane at gmail.com> wrote:
> >
> >> The terms a(1) though a(10) are: 0, 0, 4, 3, 6, 6, 3, 13, 22, 35, and
> (my) definition is that a(n) is the number of [nonnegative / positive]
> numbers whose standard name in [British / American] English has n letters,
> or -1 if there are infinitely many numbers with n letters. So there are
> really four sequences. The only difference between nonnegative and positive
> is at n=4, where we get 3 for positive numbers (four, five, nine) or 4 for
> nonnegative numbers (include zero). Up though n=10 there is no difference
> between British and American English, according to GCHQ.
>
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