A306843 - OEIS

A306843

a(n) = Sum_{d|n} binomial(n,d)^3.

1, 9, 28, 281, 126, 11592, 344, 365465, 593434, 16095134, 1332, 921113624, 2198, 40424993884, 27175280778, 2137777203097, 4914, 121331143444050, 6860, 6310445825215406, 1572228697798262, 351047164202718608, 12168, 20174300460344963864, 149975199312626

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..1000

FORMULA

If p is prime, a(p) = A001093(p).

MATHEMATICA

a[n_] := DivisorSum[n, Binomial[n, #]^3 &]; Array[a, 25] (* Amiram Eldar, Jun 13 2021 *)

PROG

(PARI) {a(n) = sumdiv(n, d, binomial(n, d)^3)}

CROSSREFS