OFFSET
1,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..335
N. J. A. Sloane, Transforms
FORMULA
a(n) = (1/n)*Sum_{d|n} sigma(d)^d*moebius(n/d).
MAPLE
A158947 := proc(n) add(numtheory[sigma](d)^d*numtheory[mobius](n/d), d=numtheory[divisors](n))/n ; end: seq( A158947(n), n=1..40) ; # R. J. Mathar, Apr 02 2009
# The function EulerInvTransform is defined in A358451.
a := EulerInvTransform(A156217):
seq(a(n), n = 1..17); # Peter Luschny, Nov 21 2022
MATHEMATICA
f[n_] := Block[{d = Divisors@n}, Plus @@ (DivisorSigma[1, d]^d*MoebiusMu[n/d])/n]; Array[f, 17] (* Robert G. Wilson v, May 04 2009 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, Mar 31 2009
EXTENSIONS
Extended by R. J. Mathar, Apr 02 2009
STATUS
approved