A193388 Sum of even divisors of phi(n).

0, 0, 2, 2, 6, 2, 8, 6, 8, 6, 12, 6, 24, 8, 14, 14, 30, 8, 26, 14, 24, 12, 24, 14, 36, 24, 26, 24, 48, 14, 48, 30, 36, 30, 56, 24, 78, 26, 56, 30, 84, 24, 64, 36, 56, 24, 48, 30, 64, 36, 62, 56, 84, 26, 84, 56, 78, 48, 60, 30, 144, 48, 78, 62, 120, 36, 96

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Formula

a(n) = A146076(A000010(n)) = A062402(n) - A193454(n). - Antti Karttunen, Dec 05 2017

Example

a(13) = 24 because phi(13) = 12 and the sum of the 4 even divisors { 2, 4, 6, 12} is 24.

Mathematica

Table[Total[Select[Divisors[EulerPhi[n]], EvenQ[ # ]&]], {n, 58}]

Prog

(PARI) A193388(n) = { my(s=eulerphi(n)); sumdiv(s, d, (!(d%2))*d); }; \\ Antti Karttunen, Dec 05 2017

Crossrefs

Cf. A000010, A062402, A146076, A193454.

Cf. also A193322, A193386.

Sequence in context: A233591 A071052 A305984 * A291840 A208448 A096869

Adjacent sequences: A193385 A193386 A193387 * A193389 A193390 A193391

Keyword

nonn

Author

Michel Lagneau, Jul 25 2011

Status

approved