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Number of partitions of n into parts 5k+2 or 5k+4.
1

%I #8 Aug 27 2015 05:58:15

%S 0,1,0,2,0,2,1,3,2,3,3,5,4,7,5,10,7,13,10,16,15,20,20,26,26,34,33,45,

%T 42,56,55,70,71,86,91,109,113,136,140,170,174,209,217,255,270,311,331,

%U 381,404,465,491,565,597,681,726,820,878,985,1056,1185,1265,1419,1515

%N Number of partitions of n into parts 5k+2 or 5k+4.

%F a(n) ~ exp(2*Pi*sqrt(n/15)) * Gamma(2/5) * Gamma(4/5) / (4 * 3^(7/20) * 5^(3/20) * Pi^(4/5) * n^(17/20)). - _Vaclav Kotesovec_, Aug 27 2015

%t nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(5k+2))*(1 - x^(5k+4))), {k, 0, nmax}], {x, 0, nmax}], x]] (* _Vaclav Kotesovec_, Aug 27 2015 *)

%K nonn

%O 1,4

%A _Olivier Gérard_