OFFSET
1,7
LINKS
Indranil Ghosh, Table of n, a(n) for n = 1..10000
FORMULA
EXAMPLE
a(63) = 13 because phi(63) = 36, and the sum of the 3 odd divisors {1, 3, 9} is 13.
MATHEMATICA
Table[Total[Select[Divisors[EulerPhi[n]], OddQ[ # ]&]], {n, 58}]
PROG
(PARI) a(n) = sumdiv(eulerphi(n), d, (d%2)*d); \\ Michel Marcus, Jan 14 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jul 26 2011
STATUS
approved