|
|
A193454
|
|
Sum of odd divisors of phi(n).
|
|
3
|
|
|
1, 1, 1, 1, 1, 1, 4, 1, 4, 1, 6, 1, 4, 4, 1, 1, 1, 4, 13, 1, 4, 6, 12, 1, 6, 4, 13, 4, 8, 1, 24, 1, 6, 1, 4, 4, 13, 13, 4, 1, 6, 4, 32, 6, 4, 12, 24, 1, 32, 6, 1, 4, 14, 13, 6, 4, 13, 8, 30, 1, 24, 24, 13, 1, 4, 6, 48, 1, 12, 4, 48, 4, 13, 13, 6, 13, 24, 4
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,7
|
|
COMMENTS
|
Phi(n): A000010 is the Euler totient function. This sequence equals A193254(n) for n < 63.
|
|
LINKS
|
|
|
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
|
|
|
STATUS
|
approved
|
|
|
|