1,3

The large terms, for example at n=41, correspond to the perfect numbers A000396 in A007691. See A134666 for the number of multiply perfect numbers having a given highest exponent of 2.

T. D. Noe, Table of n, a(n) for n=1..5000 (using Flammenkamp's data)

Achim Flammenkamp, The Multiply Perfect Numbers Page

a(n) = A007814(A007691(n)). - Michel Marcus, Oct 10 2017

Cf. A007814, A007691.

Sequence in context: A245349 A122416 A307784 * A271832 A063260 A271859

Adjacent sequences: A134662 A134663 A134664 * A134666 A134667 A134668

nonn

T. D. Noe, Nov 05 2007

approved