A193336 Sum of even divisors of sigma(n).

0, 0, 6, 0, 8, 24, 14, 0, 0, 26, 24, 48, 16, 56, 56, 0, 26, 0, 36, 64, 62, 78, 56, 144, 0, 64, 84, 112, 48, 182, 62, 0, 120, 80, 120, 0, 40, 144, 112, 156, 64, 248, 72, 192, 112, 182, 120, 192, 0, 0, 182, 114, 80, 336, 182, 336, 180, 156, 144, 448, 64, 248, 196, 0, 192, 390, 108, 208, 248, 390, 182, 0, 76, 160, 192, 288, 248, 448, 180, 256, 0

Offset: 1

Author

Michel Lagneau, Jul 23 2011

Keywords

• nonn

Comments

sigma(n) = sum of divisors of n: A000203 (also called sigma_1(n)).

Examples

			a(14) = 56 because sigma(14) = 24 and the sum of the 6 even divisors {2, 4, 6, 8, 12, 24} is 56.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384
• Index entries for sequences related to sigma(n).
• Index entries for sequences related to sums of divisors.

Crossrefs

Cf. A000203, A028982, A051027, A146076, A193334, A193337.

Programs

Mathematica

Table[Total[Select[Divisors[DivisorSigma[1,n]], EvenQ[ # ]&]], {n, 53}]

PARI

A193336(n) = { my(s=sigma(n)); sumdiv(s,d,(!(d%2))*d); }; \\ Antti Karttunen, Nov 18 2017

Formula

a(n) + A193337(n) = A051027(n). - Antti Karttunen, Nov 18 2017

From Amiram Eldar, Mar 30 2024: (Start)

a(n) = A146076(A000203(n)).

a(n) = 0 if and only if n is in A028982. (End)

Extensions

More terms from Antti Karttunen, Nov 18 2017