OFFSET
0,5
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..10000
MAPLE
with(numtheory):
d:= n-> n*add(i[2]*pi(i[1])/i[1], i=ifactors(n)[2]):
A:= proc(n, k) option remember; `if`(k=0, n, d(A(n, k-1))) end:
a:= n-> A(n, 2):
seq(a(n), n=0..100);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jun 12 2015
STATUS
approved