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A005398
Number of n-step polygons on f.c.c. lattice.
(Formerly M4512)
2
8, 33, 168, 970, 6168, 42069, 301376, 2241420, 17173224, 134806948, 1079802216, 8798329080, 72748583832, 609220407150, 5158999447488
OFFSET
3,1
REFERENCES
A. J. Guttmann, Polygons, Polyominoes and Polycubes, Lecture Notes in Physics Volume 775, 2009, Chapter 16.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
MATHEMATICA
A001337 = Cases[Import["https://oeis.org/A001337/b001337.txt", "Table"], {_, _}][[All, 2]];
a[n_] := A001337[[n]]/(2n);
a /@ Range[3, 17] (* Jean-François Alcover, Jan 20 2020 *)
CROSSREFS
Equals A001337(n) / (2n).
Sequence in context: A220590 A183776 A001407 * A240044 A069509 A204191
KEYWORD
nonn,more,nice
EXTENSIONS
More terms from Ruperto Corso, Dec 19 2011
a(15) and a(16) from Sean A. Irvine, Mar 30 2017
a(17) from Bert Dobbelaere, Jan 14 2019
STATUS
approved