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

Neil Sloane njasloane at gmail.com
Wed Jun 24 21:47:55 CEST 2020


I will follow Fred's advice, as always.


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 Wed, Jun 24, 2020 at 3:01 PM Sean A. Irvine <sairvin at gmail.com> wrote:

> I'm with Fred on this.  The current values are all correct and consistent,
> but indeed a(0)=1 could be inserted as Fred suggests.
>
>
> On Thu, 25 Jun 2020 at 03:51, Fred Lunnon <fred.lunnon at gmail.com> wrote:
>
> >   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
> > >
> > >
> > > --
> > > Seqfan Mailing list - http://list.seqfan.eu/
> > >
> >
> > --
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> >
>
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