A134740 Number of distinct prime factors in the n-th multiply perfect number A007691(n).

0, 2, 2, 3, 2, 3, 2, 4, 5, 4, 6, 5, 2, 5, 6, 6, 7, 5, 2, 7, 7, 6, 6, 6, 2, 7, 7, 7, 6, 8, 8, 8, 8, 6, 7, 8, 8, 9, 7, 8, 2, 9, 9, 9, 11, 10, 9, 10, 10, 8, 9, 11, 10, 10, 8, 11, 11, 10, 10, 11, 11, 9, 11, 9, 12, 11, 13, 13, 12, 11, 12, 12, 11, 13, 12, 12, 12, 11, 12, 13, 12, 11, 10, 13, 12, 11, 10

Offset: 1

Author

T. D. Noe, Nov 07 2007

Keywords

• nonn

Comments

If a multiply perfect number k has abundancy m = sigma(k)/k, then k must have at least A005579(m) distinct prime factors.

Links

• T. D. Noe, Table of n, a(n) for n=1..5000 (using Flammenkamp's data)
• Achim Flammenkamp, The Multiply Perfect Numbers Page

Crossrefs

Cf. A007691.