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

1,3

Links

Table of n, a(n) for n=1..59.

Formula

a(n) = Sum_{d|n} binomial(d+n/d-2,d).

If p is prime, a(p) = p - 1.

Prog

(PARI) a(n) = sumdiv(n, d, binomial(d+n/d-2, d));

Crossrefs

Cf. A081543, A366975.

Cf. A318636.

Sequence in context: A187209 A006579 A227906 * A346004 A195727 A256701

Adjacent sequences: A366971 A366972 A366973 * A366975 A366976 A366977

Keyword

nonn

Author

Seiichi Manyama, Oct 30 2023

Status

approved