OFFSET
3,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 3..1000
FORMULA
a(n) = [x^n y^3] 1/Product_{j>=1} (1-y*x^j)^A027306(j).
MAPLE
g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
b:= proc(n, i) option remember; series(`if`(n=0 or i=1, x^n, add(
binomial(g(i)+j-1, j)*b(n-i*j, i-1)*x^j, j=0..n/i)), x, 4)
end:
a:= n-> coeff(b(n$2), x, 3):
seq(a(n), n=3..33);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 02 2018
STATUS
approved