A035380 - OEIS

A035380

Number of partitions of n into parts 6k+1 or 6k+2.

1, 2, 2, 3, 3, 4, 5, 7, 8, 10, 11, 13, 15, 19, 22, 27, 30, 35, 39, 46, 53, 62, 70, 80, 89, 102, 115, 133, 149, 169, 187, 211, 235, 266, 297, 333, 368, 410, 454, 508, 563, 628, 691, 765, 841, 932, 1027, 1136, 1247, 1372, 1502, 1653, 1812, 1993, 2179, 2388

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..56.

FORMULA

a(n) ~ exp(Pi*sqrt(2*n)/3) * Gamma(1/6) * Gamma(1/3) / (4 * Pi^(3/2) * sqrt(6*n)). - Vaclav Kotesovec, Aug 27 2015

MATHEMATICA

nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(6k+1))*(1 - x^(6k+2))), {k, 0, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Aug 27 2015 *)

CROSSREFS

Sequence in context: A286219 A117357 A029020 * A036823 A035575 A036816

Adjacent sequences: A035377 A035378 A035379 * A035381 A035382 A035383

KEYWORD

nonn

AUTHOR

Olivier Gérard

STATUS

approved