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A307741 Sum of divisors of multiply-perfect numbers. 1
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

Table of n, a(n) for n=1..26.

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 October 20 10:00 EDT 2019. Contains 328257 sequences. (Running on oeis4.)