OFFSET
1,3
COMMENTS
Fixed points are in A074701.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10001
FORMULA
MAPLE
MATHEMATICA
Table[Sum[MoebiusMu[EulerPhi[d]] EulerPhi[n]/d, {d, Divisors[EulerPhi[n]]}], {n, 100}] (* Indranil Ghosh, Jul 17 2017 *)
PROG
(PARI) A163167(n) = sumdiv(eulerphi(n), d, moebius(eulerphi(d))*eulerphi(n)/d); \\ Antti Karttunen, Jul 17 2017
(PARI)
A289627(n) = sumdiv(n, d, moebius(eulerphi(d))*n/d);
(Python)
from sympy import mobius, totient, divisors
def a(n):
tn = totient(n)
return sum(mobius(totient(d))*tn//d for d in divisors(tn))
print([a(n) for n in range(1, 51)]) # Indranil Ghosh, Jul 17 2017
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
R. J. Mathar, Jul 22 2009
STATUS
approved