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A120481

Number of prime divisors of F(n) + L(n), where F(n) is the n-th Fibonacci number and L(n) is the n-th Lucas number.

+0
1

1, 1, 2, 2, 1, 2, 3, 2, 3, 2, 2, 2, 3, 3, 4, 2, 3, 3, 5, 3, 3, 2, 4, 3, 3, 4, 5, 2, 5, 3, 5, 3, 3, 4, 5, 4, 4, 3, 7, 3, 5, 2, 6, 5, 4, 2, 6, 4, 6, 3, 5, 3, 6, 5, 7, 5, 4, 3, 8, 3, 4, 5, 7, 4, 5, 4, 6, 5, 8, 3, 8, 3, 5, 5, 6, 5, 6, 3, 10, 7, 4, 2, 9, 5, 4, 4, 10, 3, 10, 5, 7, 4, 3, 7, 9, 5, 6, 6, 10, 3 (list; graph; listen)

	OFFSET	`1,3`
	LINKS	`Eric Weisstein's World of Mathematics, Fibonacci Number` `Eric Weisstein's World of Mathematics, Lucas Number`
	EXAMPLE	`F(30) + L(30) = 2692538, which has the 3 prime divisors {2, 557, 2417}, so a(30) = 3.`
	MATHEMATICA	`Do[f = Fibonacci[n]; l = Fibonacci[n-1] + Fibonacci[n+1]; Print[Length[FactorInteger[f + l]]], {n, 100}]`
	CROSSREFS	`Sequence in context: A091972 A025833 A035462 this_sequence A029291 A022872 A091423` `Adjacent sequences: A120478 A120479 A120480 this_sequence A120482 A120483 A120484`
	KEYWORD	`nonn`
	AUTHOR	`Ryan Propper (rpropper(AT)stanford.edu), Jul 21 2006`

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Last modified September 7 15:23 EDT 2008. Contains 143483 sequences.

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