A366974 Expansion of Sum_{k >=1} x^(2*k)/(1-x^k)^(k+1).
0, 1, 2, 4, 4, 9, 6, 14, 12, 20, 10, 42, 12, 35, 40, 59, 16, 96, 18, 121, 84, 77, 22, 281, 80, 104, 156, 281, 28, 521, 30, 407, 264, 170, 406, 1083, 36, 209, 416, 1418, 40, 1514, 42, 1068, 1632, 299, 46, 3532, 840, 1923, 884, 1847, 52, 3824, 2420, 5377, 1216, 464, 58
Offset: 1
Keywords
Programs
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PARI
a(n) = sumdiv(n, d, binomial(d+n/d-2, d));
Formula
a(n) = Sum_{d|n} binomial(d+n/d-2,d).
If p is prime, a(p) = p - 1.