[seqfan] Re: More terms for needed for A086748, Numbers m such that when C(2k, k) == 1 (mod m) then k is necessarily even.

[Antti Karttunen]

On Tue, Jul 9, 2024 at 10:23 PM Antti Karttunen <antti.karttunen at gmail.com>
wrote:

>
> Cheers all,
>
> I just encountered sequence https://oeis.org/A086748 in somewhat
> unexpected connection (well, unexpected at least on the first sight).
> The first 58 terms match, from 3 to 245, but after that I cannot check,
> because I don't understand A086748's definition well enough to write a
> program for it.
> (And it seems that it might be hard to compute as well). I can easily
> compute my own sequence (that might be same or might eventually differ) for
> terms that are in range 1 .. 2^21.
>
> Is anybody familiar with this sequence?
>
>
Well, now I wonder if it is just the complement of
https://oeis.org/A007775 (Numbers not divisible by 2, 3 or 5).
among the odd numbers? I.e., odd numbers that are not 7-rough numbers,
i.e., odd numbers that are either multiples of 3 or 5?


Best regards,

Antti


>
> Best regards,
>
> Antti
>
>