OFFSET
1,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..5000
FORMULA
a(n) ~ 3^((n - 3 - mod(n,3))/3). - Vaclav Kotesovec, May 28 2021
G.f.: (1/(1 - x)) * Sum_{k>=1} x^k * (1 - x^k)/(1 - k*x^k). - Seiichi Manyama, Jun 06 2021
MATHEMATICA
Table[Sum[k^Floor[(n - k)/k], {k, n}], {n, 80}]
PROG
(PARI) a(n) = sum(k=1, n, k^(n\k-1)); \\ Seiichi Manyama, Jun 06 2021
(PARI) my(N=66, x='x+O('x^N)); Vec(sum(k=1, N, x^k*(1-x^k)/(1-k*x^k))/(1-x)) \\ Seiichi Manyama, Jun 06 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, May 22 2021
STATUS
approved