id:A127992 - OEIS Search Results

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Number of different prime factors of 2n^3 - 2n + 9.

+0
4

1, 2, 2, 2, 2, 3, 2, 2, 3, 3, 2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 4, 2, 3, 3, 3, 3, 3, 3, 2, 4, 3, 2, 2, 3, 3, 2, 3, 2, 3, 2, 3, 4, 3, 2, 3, 2, 4, 3, 4, 3, 2, 2, 3, 2, 2, 4, 2, 3, 4, 3, 3, 3, 4, 3, 2, 2, 2, 3, 3, 4, 3, 3, 4, 3, 3, 4, 4, 2, 2, 2, 3, 3, 3, 4, 3, 4, 2, 3, 2, 2, 3, 3, 3, 2, 4, 3, 2, 3, 4, 2, 3, 2, 4 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`All numbers generated by the irreducible polynomial 2n^3 - 2n + 9 (A127979) are odd and composite. Largest prime factor A127990, number of prime factors A127992`
	MATHEMATICA	`a = {}; Do[AppendTo[a, 2n^3 - 2n + 9], {n, 1, 300}]; b = {}; Do[c = FactorInteger[a[[n]]]; d = Length[c]; AppendTo[b, d], {n, 1, Length[a]}]; b (Artur Jasinski)`
	CROSSREFS	`Cf. A127979, A127990.` `Sequence in context: A033618 A061357 A138139 this_sequence A067595 A134868 A127417` `Adjacent sequences: A127989 A127990 A127991 this_sequence A127993 A127994 A127995`
	KEYWORD	`nonn`
	AUTHOR	`Artur Jasinski (grafix(AT)csl.pl), Feb 10 2007`

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Last modified December 17 13:29 EST 2009. Contains 170826 sequences.

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