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 A307741 Sum of divisors of multiply-perfect numbers. 2
 1, 12, 56, 360, 992, 2016, 16256, 120960, 131040, 1571328, 8714160, 94279680, 67100672, 182131200, 571963392, 1379454720, 5517818880, 4428914688, 17179738112, 70912195200, 159991977600, 175445913600, 153003540480, 265734881280, 274877382656, 612014161920 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) = sigma(A007691(n)) = A000203(A007691(n)). When sorted, this is A081756. - N. J. A. Sloane, May 03 2019 LINKS FORMULA a(n) = A007691(n) * A054030(n). EXAMPLE For n = 3; a(3) = sigma(A007691(3)) = sigma(28) = 56. PROG (MAGMA) [SumOfDivisors(n): n in [1..1000000] | IsIntegral(SumOfDivisors(n)/n)] (PARI) lista(nn) = {for (n=1, nn, my(s=sigma(n)); if (! (s % n), print1(s, ", ")); ); } \\ Michel Marcus, Apr 26 2019 CROSSREFS Cf. A000203, A007691, A054030, A088843 (tau(A007691)), A139256. See also A081756. Sequence in context: A068414 A199316 A081756 * A027147 A095724 A225880 Adjacent sequences:  A307738 A307739 A307740 * A307742 A307743 A307744 KEYWORD nonn AUTHOR Jaroslav Krizek, Apr 26 2019 STATUS approved

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Last modified January 18 16:27 EST 2022. Contains 350455 sequences. (Running on oeis4.)