A308423 Product of divisors of multiply-perfect numbers.

1, 36, 21952, 42998169600000000, 30019840638976, 8480691722056324948490652657647616, 2343612817652433441167245312

Offset

1,2

Comments

a(8) has 216 digits (116929951...000000000).

Supersequence of A067584.

Links

Table of n, a(n) for n=1..7.

Formula

a(n) = A007955(A007691(n)).

Example

For n = 3; a(3) = A007955(A007691(3)) = A007955(28) = 21952.

Mathematica

s = {}; Do[If[Divisible[DivisorSigma[1, n], n], AppendTo[s, n^(DivisorSigma[0, n]/2)]], {n, 10^4}]; s (* Amiram Eldar, Jul 04 2019 *)

Prog

(Magma) [&*[d: d in Divisors(m)]: m in [1..10^5] | IsIntegral(SumOfDivisors(m)/m)]

Crossrefs

Cf. A007691, A007955, A067584.

See A088843 and A307741 for the number of and the sum of divisors of multiply-perfect numbers.

Sequence in context: A271338 A001308 A067584 * A146521 A159431 A028454

Adjacent sequences: A308420 A308421 A308422 * A308424 A308425 A308426

Keyword

nonn

Author

Jaroslav Krizek, May 26 2019

Status

approved