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Number of partitions of n into parts 7k or 7k+2.
0

%I #8 Aug 27 2015 06:09:42

%S 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,

%T 23,12,25,19,26,31,26,40,26,45,37,47,56,48,73,48,83,63,88,93,90,121,

%U 91,140,113,150,158,155,205,157,238,188,258,255,268,328,273,385,317

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

%F 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

%t 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 *)

%K nonn

%O 1,9

%A _Olivier Gérard_