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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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
sigma(n) = sum of divisors of n: A000203 (also called sigma_1(n)).
LINKS
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
Sequence in context: A153609 A156015 A201898 * A240251 A114530 A085673
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jul 23 2011
EXTENSIONS
More terms from Antti Karttunen, Nov 18 2017
STATUS
approved

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Last modified June 24 22:33 EDT 2024. Contains 373690 sequences. (Running on oeis4.)