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A134740 Number of distinct prime factors in the n-th multiply perfect number A007691(n). 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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

Sequence in context: A229123 A173908 A054030 * A054714 A235922 A255598

Adjacent sequences:  A134737 A134738 A134739 * A134741 A134742 A134743

KEYWORD

nonn

AUTHOR

T. D. Noe, Nov 07 2007

STATUS

approved

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Last modified December 12 07:03 EST 2018. Contains 318052 sequences. (Running on oeis4.)