OFFSET
0,2
COMMENTS
A007219 is the main entry for golygons.
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood City, CA, 1991, p. 92.
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..200
Eric Weisstein's World of Mathematics, Golygon
FORMULA
a(n) = 4 * A007219(n) for n > 0. - Charles R Greathouse IV, Apr 29 2012
MATHEMATICA
p1[n_] := Product[x^k + 1, {k, 1, n - 1, 2}] // Expand; p2[n_] := Product[x^k + 1, {k, 1, n/2}] // Expand; c[n_] := Coefficient[p1[n], x, n^2/8] * Coefficient[p2[n], x, n (n/2 + 1)/8]; a[n_] := c[8*n]; Table[a[n], {n, 0, 11}] (* Jean-François Alcover, Jul 24 2013, after Eric W. Weisstein *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(0) = 1 prepended by Seiichi Manyama, Sep 18 2017
STATUS
approved