A035391 - OEIS

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A035391

Number of partitions of n into parts 7k or 7k+2.

0, 1, 0, 1, 0, 1, 1, 1, 2, 1, 2, 1, 2, 3, 2, 5, 2, 6, 2, 6, 5, 6, 9, 6, 11, 6, 12, 11, 12, 18, 12, 23, 12, 25, 19, 26, 31, 26, 40, 26, 45, 37, 47, 56, 48, 73, 48, 83, 63, 88, 93, 90, 121, 91, 140, 113, 150, 158, 155, 205, 157, 238, 188, 258, 255, 268, 328, 273, 385, 317

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OFFSET

1,9

LINKS

Table of n, a(n) for n=1..70.

FORMULA

a(n) ~ exp(2*Pi*sqrt(n/21)) * Gamma(2/7) / (4 * 3^(11/28) * 7^(3/28) * Pi^(5/7) * n^(25/28)). - Vaclav Kotesovec, Aug 27 2015

MATHEMATICA

nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(7k+7))*(1 - x^(7k+2))), {k, 0, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Aug 27 2015 *)

CROSSREFS

Sequence in context: A358997 A373461 A257806 * A242552 A249717 A249718

Adjacent sequences: A035388 A035389 A035390 * A035392 A035393 A035394

KEYWORD

nonn

AUTHOR

Olivier Gérard

STATUS

approved