OFFSET
1,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..1431
FORMULA
a(n) = A054720(n)/5 for n > 0.
G.f.: Sum_{k>=1} mu(k)*x^k/(1 - 5*x^k). - Ilya Gutkovskiy, Oct 25 2018
MATHEMATICA
nmax = 20; Rest[CoefficientList[Series[Sum[MoebiusMu[k] * x^k / (1 - 5*x^k), {k, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Dec 11 2020 *)
PROG
(PARI) {a(n) = sumdiv(n, d, moebius(n/d)*5^(d-1))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 23 2017
STATUS
approved