1,3

The first n-fold perfect numbers are A007539(n) = 1, 6, 120, 30240, 14182439040, ..., for n = 1, 2, 3, 4, 5, ...

The first n-fold perfect numbers divided by 120 is A227766.

The first n-fold perfect numbers divided by 30240 is A227767.

The first n-fold perfect numbers divided by 14182439040 is A227768.

For additional comments, references, links, and cross-refs, see A007539.

T. D. Noe, Table of n, a(n) for n = 1..8

E. W. Weisstein's MathWorld, Multiperfect Number

Wikipedia, Multiply perfect number

a(n) = A007539(n)/6 if 2 <= n <= 8.

The first 3-fold perfect number is A007539(3) = 120, so a(3) = 120/6 = 20.

Cf. A007539, A227766, A227767, A227768, A227769.

Sequence in context: A279297 A079759 A109894 * A250020 A088852 A123379

Adjacent sequences: A227762 A227763 A227764 * A227766 A227767 A227768

nonn

Jonathan Sondow, Jul 29 2013

approved