id:A050340 - OEIS Search Results

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Number of ways of factoring n with 3 levels of parentheses.

+0
2

1, 1, 1, 5, 1, 5, 1, 15, 5, 5, 1, 25, 1, 5, 5, 55, 1, 25, 1, 25, 5, 5, 1, 105, 5, 5, 15, 25, 1, 35, 1, 170, 5, 5, 5, 145, 1, 5, 5, 105, 1, 35, 1, 25, 25, 5, 1, 425, 5, 25, 5, 25, 1, 105, 5, 105, 5, 5, 1, 205, 1, 5, 25, 571, 5, 35, 1, 25, 5, 35, 1, 660, 1, 5, 25, 25, 5, 35, 1, 425, 55, 5 (list; graph; listen)

	OFFSET	`1,4`
	COMMENT	`a(n) depends only on prime signature of n (cf. A025487). So a(24) = a(375) since 24=2^33 and 375=35^3 both have prime signature (3,1).`
	FORMULA	`Dirichlet g.f.: prod{n=2 to inf}(1/(1-1/n^s)^A050338(n)).`
	EXAMPLE	`4=(((4)))=(((22)))=(((2)(2)))=(((2))((2)))=(((2)))(((2))).`
	CROSSREFS	`Cf. A001055, A050336-A050341. a(p^k)=A007714. a(A002110)=A000357.` `Sequence in context: A100947 A096940 A141345 this_sequence A021955 A055191 A060186` `Adjacent sequences: A050337 A050338 A050339 this_sequence A050341 A050342 A050343`
	KEYWORD	`nonn`
	AUTHOR	`Christian G. Bower (bowerc(AT)usa.net), Oct 15 1999.`

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

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