A035367 Number of partitions of n into parts 5k or 5k+1.
1, 1, 1, 1, 2, 3, 3, 3, 3, 5, 7, 8, 8, 8, 11, 15, 17, 18, 18, 23, 30, 35, 37, 38, 45, 57, 66, 71, 73, 85, 104, 121, 131, 136, 153, 184, 212, 231, 241, 268, 315, 363, 396, 416, 456, 528, 603, 661, 696, 758, 865, 984, 1078, 1141, 1233, 1392, 1572, 1724, 1828, 1970
Offset: 1
Keywords
Programs
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Mathematica
nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(5k+5))*(1 - x^(5k+1))), {k, 0, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Aug 27 2015 *)
Formula
a(n) ~ exp(2*Pi*sqrt(n/15)) * Gamma(1/5) / (4 * 3^(7/20) * 5^(3/20) * Pi^(4/5) * n^(17/20)). - Vaclav Kotesovec, Aug 27 2015