A307741 Sum of divisors of the multiply-perfect numbers.

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

Offset

1,2

Comments

When sorted, this is A081756. - N. J. A. Sloane, May 03 2019

Links

Amiram Eldar, Table of n, a(n) for n = 1..730

Formula

a(n) = sigma(A007691(n)) = A000203(A007691(n)).

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