[seqfan] Re: Looking for sequence N1209
njasloane at gmail.com
Tue Jun 12 15:01:42 CEST 2012
Joseph, Thanks very much for that message! I used it
in reconstructing N1209, which is now A213451.
On Tue, Jun 12, 2012 at 5:42 AM, Joseph S. Myers <jsm at polyomino.org.uk>wrote:
> On Mon, 11 Jun 2012, Neil Sloane wrote:
> > Dear SeqFans,
> > In the 1973 Handbook there appears this sequence, N1209:
> > 1,3,15,69,309,1365,5973,25941,112065,482067,2066583,...
> > It was omitted from the 1995 book, but I can't recall why.
> > The definition was WALKS ON A TRIANGULAR LATTICE, and it appeared on
> > page 354 of a very long paper by Domb:
> FWIW, related sequences appear under the description of "triangular strip
> polyedges" (where A151540 is one-sided triangular strip polyedges and
> A151541 is two-sided / free triangular strip polyedges, this would seem to
> be fixed triangular strip polyedges). Ignoring the initial 1 (offset 0, I
> suppose), the initial 13 terms (fixed triangular strip polyedges with 1 to
> 13 edges) are: 3, 15, 69, 309, 1365, 5973, 25941, 112065, 482067, 2066583,
> 8834469, 37677603, 160367343.
> Joseph S. Myers
> jsm at polyomino.org.uk
> Seqfan Mailing list - http://list.seqfan.eu/
Dear Friends, I have now retired from AT&T. New coordinates:
Neil J. A. Sloane, President, OEIS Foundation
11 South Adelaide Avenue, Highland Park, NJ 08904, USA
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com
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