A193454 Sum of odd divisors of phi(n).

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

Offset

1,7

Comments

Phi(n): A000010 is the Euler totient function. This sequence equals A193254(n) for n < 63.

Links

Indranil Ghosh, Table of n, a(n) for n = 1..10000

Formula

a(n) = A000593(A000010(n)). - Michel Marcus, Jan 14 2014

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

Cf. A000010, A193254.

Sequence in context: A257231 A196757 A193254 * A368921 A322819 A089655

Adjacent sequences: A193451 A193452 A193453 * A193455 A193456 A193457

Keyword

nonn

Author

Michel Lagneau, Jul 26 2011

Status

approved