OFFSET
1,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..387
FORMULA
a(n) = [x^n] (1/(1 - x)) * Sum_{k>=1} x^k * (1 - x^k)/(1 - n*x^k).
MATHEMATICA
a[n_] := Sum[n^(Floor[n/k] - 1), {k, 1, n}]; Array[a, 20] (* Amiram Eldar, Jun 06 2021 *)
PROG
(PARI) a(n) = sum(k=1, n, n^(n\k-1));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 06 2021
STATUS
approved