OFFSET
1,3
COMMENTS
n=5, f[5]=120, divisors={1,5} f[5/d]={120,1}, mu[d]={1,-1}, the sum is 120-1=119=a(5)
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..449
FORMULA
a(n) = Sum{f[n/d]*mu[d]}, where d|n and f[x]=A000142(x).
a(n) ~ n!. - Vaclav Kotesovec, Sep 16 2021
PROG
(PARI) a(n) = sumdiv(n, d, d!*moebius(n/d)); \\ Michel Marcus, Nov 04 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jul 19 2001
STATUS
approved