A035365 - OEIS

A035365

Number of partitions of n into parts 4k+1 or 4k+2.

1, 2, 2, 3, 4, 6, 7, 9, 11, 15, 18, 23, 27, 34, 41, 50, 59, 72, 85, 103, 120, 143, 167, 198, 230, 270, 313, 366, 422, 491, 564, 653, 748, 861, 984, 1130, 1287, 1471, 1671, 1905, 2159, 2453, 2772, 3141, 3544, 4004, 4506, 5079, 5705, 6416, 7192, 8070, 9030

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..53.

FORMULA

a(n) ~ exp(Pi*sqrt(n/3)) * Gamma(5/4) / (3^(1/8) * (2*Pi)^(3/4) * n^(5/8)). - Vaclav Kotesovec, Aug 27 2015

MATHEMATICA

nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(4k+1))*(1 - x^(4k+2))), {k, 0, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Aug 27 2015 *)

CROSSREFS

Sequence in context: A029011 A077117 A237976 * A335745 A119604 A036806

Adjacent sequences: A035362 A035363 A035364 * A035366 A035367 A035368

KEYWORD

nonn

AUTHOR

Olivier Gérard

STATUS

approved