OFFSET
1,1
LINKS
Indranil Ghosh, Table of n, a(n) for n = 1..935 (terms < 5000)
FORMULA
Sum_{k|n} mu(k+1), where mu() is Moebius function.
MATHEMATICA
f[n_] := Plus @@ MoebiusMu[Divisors[n] + 1]; Select[ Range[319], f[ # ] == 0 &]
PROG
(PARI) a(n) = sumdiv(n, k, moebius(k + 1));
for(n=1, 320, if(a(n) == 0, print1(n, ", "))) \\ Indranil Ghosh, Mar 16 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet and Robert G. Wilson v, Nov 05 2004
STATUS
approved