A366933 Expansion of Sum_{k>=1} k^4 * x^k/(1 - x^k)^4.

1, 20, 91, 340, 660, 1836, 2485, 5560, 7536, 13280, 14927, 31360, 29016, 49924, 60390, 89776, 84490, 152496, 131651, 226520, 227066, 299420, 282141, 514080, 415425, 581776, 614070, 850864, 711776, 1226520, 928977, 1442400, 1362042, 1693064, 1644930, 2609076

Offset: 1

Author

Seiichi Manyama, Oct 29 2023

Keywords

• nonn
• easy

Crossrefs

Cf. A064987, A366135, A366934.

Cf. A059358, A343544.

Cf. A343573.

Programs

PARI

a(n) = sumdiv(n, d, d^4*binomial(n/d+2, 3));

Formula

a(n) = Sum_{d|n} d^4 * binomial(n/d+2,3).