[seqfan] Re: A064736, A217579 and A302350

Neil Sloane njasloane at gmail.com
Tue Apr 17 13:13:56 CEST 2018


I guess my preference would be for "divisor-or-multiple permutations",
Yes, it is slightly ambiguous,
but it has the correct flavor.



Best regards
Neil

Neil J. A. Sloane, President, OEIS Foundation.
11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com


On Tue, Apr 17, 2018 at 6:35 AM, Antti Karttunen <antti.karttunen at gmail.com>
wrote:

> So far,
>
> After insights from Michel Marcus and Peter Munn, we have found several new
> general ways to construct these kinds of permutations where a(n) is always
> either a divisor or a multiple of a(n+1). (Mostly based on by playing the
> "Fermi-Dirac piano", A052330, with optional pre- and/or post-processing
> steps).
>
> But there remains a naming question: how to call them?
>
> There are several suggestions:
>
> Pierre Mazet & Eric Saias call them "chain permutations"
> (chaîne-permutation) in their paper https://arxiv.org/abs/1803.10073
> I assume this comes after the chains of the divisor lattice, as any two
> successive terms belong to a common chain.
>
> Then I suggested "divisor-or-multiple permutations", while Peter suggested
> "multiplicative walk permutations", but Michel objected to that, although I
> preferred it over my first proposal.
>
> I think "divisor-or-multiple permutations" is a bit ambiguous, because it
> could also mean permutations where, say, a(n) is either a divisor or
> multiple of n.
> So then we would need a phrase like "successor-is-divisor-or-multiple
> permutations", with an ugly acronym: "SIDOM permutations". No...
>
> So, I'm in favor of "multiplicative walk permutations", what would other
> people say?
>
>
> Best regards,
>
> Antti
>
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> Seqfan Mailing list - http://list.seqfan.eu/
>



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