OFFSET
0,6
LINKS
Ray Chandler, Table of n, a(n) for n = 0..3340 (terms < 10^1000)
FORMULA
a(n) is the coefficient of x^3 in product(x^(-k)+x^k, k=1..n).
MAPLE
A113037:= proc(n) local i, j, p, t; t:= NULL; for j to n do p:=1; for i to j do p:=p*(x^(-i)+x^i); od; t:=t, coeff(p, x, 3); od; t; end;
MATHEMATICA
nmax = 50; d = {1}; a1 = {};
Do[
i = Ceiling[Length[d]/2] + 3;
AppendTo[a1, If[i > Length[d], 0, d[[i]]]];
d = PadLeft[d, Length[d] + 2 n] + PadRight[d, Length[d] + 2 n];
, {n, nmax}];
a1 (* Ray Chandler, Mar 14 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Floor van Lamoen, Oct 11 2005
STATUS
approved