OFFSET
1,2
FORMULA
If p is prime, a(p) = p.
a(n) = (1/n) * Sum_{d|n} phi(d) * tau(d^n).
PROG
(PARI) a(n) = sumdiv(n, d, eulerphi(d)*numdiv(d^n))/n;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 19 2024
STATUS
approved