OFFSET
1,5
REFERENCES
See A003415
LINKS
Michel Marcus, Table of n, a(n) for n = 1..5000
MATHEMATICA
dn[0]=0; dn[1]=0; dn[n_]:=Module[{f=Transpose[FactorInteger[n]]}, If[PrimeQ[n], 1, Plus@@(n*f[[2]]/f[[1]])]]; Table[dn[EulerPhi[n]], {n, 100}]
PROG
(GAP)
A099310:= Concatenation([0, 0], List(List(List([3..10^3], n->Phi(n)), Factors), i->Product(i)*Sum(i, j->1/j))); # Muniru A Asiru, Sep 27 2017
(PARI) ad(n) = sum(i=1, #f=factor(n)~, n/f[1, i]*f[2, i]);
a(n) = ad(eulerphi(n)); \\ Michel Marcus, Sep 29 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Oct 12 2004
STATUS
approved