OFFSET
1,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = tau(n^7-1)-tau(n-1), with tau = A000005.
MAPLE
with(numtheory):
a:= n-> add(mobius(7/d) *tau(n^d-1), d={1, 7}):
seq(a(n), n=1..80);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 24 2012
STATUS
approved