A035592 Number of partitions of 3n with same number of parts == 1 (mod 3) and == 2 (mod 3).

1, 2, 6, 14, 32, 66, 134, 256, 480, 868, 1540, 2664, 4536, 7574, 12474, 20234, 32428, 51324, 80388, 124582, 191310, 291114, 439394, 657936, 978054, 1443684, 2117136, 3085174, 4469368, 6437742, 9223324, 13145792, 18644484, 26317916, 36981828

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

Cf. A035536.

Sequence in context: A188493 A055292 A327049 * A327050 A301554 A217941

Adjacent sequences: A035589 A035590 A035591 * A035593 A035594 A035595

Keyword

nonn

Author

Olivier Gérard

Extensions

More terms from David W. Wilson

Status

approved