[seqfan] Re: Can anyone explain A206159?

[D. S. McNeil]

FWIW I tried RZ's Haskell code, combining the codes from the parent
sequences:

import Data.List (group, sort)
a027750_row n = filter ((== 0) . (mod n)) [1..n]
a095048 = length . group . sort . concatMap show . a027750_row
a206159_list = filter ((<= 2) . a095048) [1..]

which looked right to me, and it generated what I think are the right
values.  So I think the sequence is _trying_ to be the one it's describing,
even if the values feel like they're coming from a similar sequence with
some additional restriction.


Doug


On Mon, May 2, 2022 at 6:30 PM Frank Adams-watters via SeqFan <
seqfan at list.seqfan.eu> wrote:

> I don't know if this helps, but the comment "apparently 1, 121 and 1111
> are the only nonprime terms" is wrong as well.
>
> The more fundamental sequence A095048 appears to be correct.
>
> A206159
>
> I'm baffled, too.
>
> Franklin T. Adams-Watters
>
>
> -----Original Message-----
> From: Neil Sloane <njasloane at gmail.com>
> To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> Cc: Harvey P. Dale <hpd at hpdale.org>
> Sent: Mon, May 2, 2022 4:32 pm
> Subject: [seqfan] Can anyone explain A206159?
>
> Harvey Dale just asked me why the numbers 2, 3, 5, 7, 22, 55, and 77 (and
> lots of others)  are missing, and I am baffled.
>
> Best regards
> Neil
>
> Neil J. A. Sloane, Chairman, OEIS Foundation.
> Also Visiting Scientist, Math. Dept., Rutgers University,
> Email: njasloane at gmail.com
>
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