OFFSET
1,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..5000
FORMULA
G.f.: Sum_{n>0} n*x^n/(1+n*x^n).
PROG
(PARI) a(n) = -sumdiv(n, d, (-n/d)^d); \\ Michel Marcus, Mar 22 2021
CROSSREFS
KEYWORD
sign
AUTHOR
Vladeta Jovovic, Oct 27 2002
STATUS
approved