OFFSET
0,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = A035536(3*n).
G.f.: (Sum_{k>=0} (-1)^k * x^(k * (k + 1)/2)) / (Product_{k>0} 1 - x^k)^3. - Michael Somos, Jul 28 2003
PROG
(PARI) {a(n) = if( n<0, 0, polcoeff( sum( k=0, (sqrtint(1 + 8*n) - 1)\2, (-1)^k * x^((k+k^2)/2)) / eta(x + x * O(x^n))^3, n))} /* Michael Somos, Jul 28 2003 */
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from David W. Wilson
STATUS
approved