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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 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

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