OFFSET
1
COMMENTS
The Moebius function mu is defined by mu(n) = (-1)^k if n is a product of k distinct primes and mu(n) = 0 otherwise.
Up to n = 10^7 this sequence only takes values in {-2, -1, 0, 1, 2}. Is this true in general?
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
FORMULA
MATHEMATICA
Table[Sum[If[GCD@@FactorInteger[d][[All, 2]]===1, MoebiusMu[n/d], 0], {d, Divisors[n]}], {n, 100}]
PROG
(PARI) A304362(n) = sumdiv(n, d, if(!ispower(d), moebius(n/d), 0)); \\ Antti Karttunen, Jul 29 2018
CROSSREFS
KEYWORD
sign
AUTHOR
Gus Wiseman, May 11 2018
EXTENSIONS
More terms from Antti Karttunen, Jul 29 2018
STATUS
approved