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A050328 Number of ordered factorizations of n into square-free numbers > 1. +0
3
1, 1, 1, 1, 1, 3, 1, 1, 1, 3, 1, 5, 1, 3, 3, 1, 1, 5, 1, 5, 3, 3, 1, 7, 1, 3, 1, 5, 1, 13, 1, 1, 3, 3, 3, 13, 1, 3, 3, 7, 1, 13, 1, 5, 5, 3, 1, 9, 1, 5, 3, 5, 1, 7, 3, 7, 3, 3, 1, 31, 1, 3, 5, 1, 3, 13, 1, 5, 3, 13, 1, 25, 1, 3, 5, 5, 3, 13, 1, 9, 1, 3, 1, 31, 3, 3, 3, 7, 1, 31, 3, 5, 3, 3, 3, 11, 1, 5 (list; graph; listen)
OFFSET

1,6

COMMENT

a(n) depends only on prime signature of n (cf. A025487). So a(24) = a(375) since 24=2^3*3 and 375=3*5^3 both have prime signature (3,1).

FORMULA

Dirichlet g.f.: 1/(1-B(s)) where B(s) is d.g.f. of characteristic function of square-free numbers > 1.

a(n) = Sum_{d divides n, d<n} A010052(n/d)*a(d). - Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 25 2002

CROSSREFS

Cf. A002033, A005117, A050329. a(p^k)=1. a(A002110)=A000670.

Sequence in context: A095960 A029356 A114006 this_sequence A030401 A166030 A132890

Adjacent sequences: A050325 A050326 A050327 this_sequence A050329 A050330 A050331

KEYWORD

nonn

AUTHOR

Christian G. Bower (bowerc(AT)usa.net), Oct 15 1999.

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Last modified December 5 20:25 EST 2009. Contains 170428 sequences.


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