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

1,3

Comments

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

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.

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)

Example

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

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A153609 A156015 A201898 * A240251 A114530 A085673

Adjacent sequences: A193333 A193334 A193335 * A193337 A193338 A193339

Keyword

nonn

Author

Michel Lagneau, Jul 23 2011

Extensions

More terms from Antti Karttunen, Nov 18 2017

Status

approved