[seqfan] Re: Polyominoes (A000105, A000988, A001168) - offset problem

[Allan Wechsler]

If the question is, "Does OEIS acknowledge Wikipedia as the ultimate
arbiter of the definition of mathematical terms?", then I am fairly sure
that the answer is "no".

There are many, many sensible reasons to admit the empty set of cells as a
0-omino, and few serious reasons not to.

On Thu, Jun 25, 2020 at 12:37 AM Jean-Luc Manguin <
jean-luc.manguin at unicaen.fr> wrote:

> Again, I refer to the definition of polyominoes (
> https://en.wikipedia.org/wiki/Polyomino) : "A polyomino is a plane
> geometric figure formed by joining one or more equal squares edge to edge."
>
> "One or more", this is clear... (unless someone can prove that zero is
> more than one)
>
> I agree that they should cross-refer (and that is another reason to put
> the same offset value).
>
> JLM
>
> ----- Mail original -----
> De: "Fred Lunnon" <fred.lunnon at gmail.com>
> À: "seqfan" <seqfan at list.seqfan.eu>
> Envoyé: Mercredi 24 Juin 2020 17:51:37
> Objet: [seqfan] Re: Polyominoes (A000105, A000988, A001168) - offset
> problem
>
> A000105 with offset = 0  is correct as it currently stands:
> there is 1 empty polyomino with  #cells = 0 .
>
>   My preference would be to attach an extra 1 at the front of both
> A000988 and A001168 , and edit to  offset = 0.
>
>   All three should cross-refer to the others; and similar remarks
> may apply to related sequences, such as A030228.   NJAS ?
>
> Fred Lunnon
>
>
> On 6/24/20, Jean-Luc Manguin <jean-luc.manguin at unicaen.fr> wrote:
> > Hello,
> >
> > Everytime I edit a sequence, I receive justified remarks about my
> > non-respect of some rules, although of course this non-respect is not
> done
> > by purpose.
> >
> > In return, I would like to find in OEIS a care about coherence ; this
> > example needs (IMO) a little correction :
> > - A000105 has an offset = 0
> > - A000988 and A001168 have offset = 1
> >
> > These three sequences give the number of polyominoes (free, one-sided,
> and
> > fixed) and as it is written in the dedicated page in Mathworld, [
> > https://mathworld.wolfram.com/Polyomino.html |
> > https://mathworld.wolfram.com/Polyomino.html ] , there is no polyomino
> with
> > zero cell ; then I would be pleased to see A000105 with offset = 1, which
> > seems much more logical. Of course I could edit this sequence (I did not
> > try, I guess I can), but I prefer to mention this in the list.
> >
> > Thank you, dear editors, for your attention to this message.
> > Have a nice day and a happy St John !
> >
> > JL Manguin
> >
> >
> > --
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> >
>
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