A193336 - OEIS

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A193336

Sum of even divisors of sigma(n).

2

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

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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