A056123 - OEIS

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A056123

a(n)=3a(n-1)-a(n-2); a(0)=1, a(1)=11.

1, 11, 32, 85, 223, 584, 1529, 4003, 10480, 27437, 71831, 188056, 492337, 1288955, 3374528, 8834629, 23129359, 60553448, 158530985, 415039507, 1086587536, 2844723101, 7447581767, 19498022200, 51046484833, 133641432299 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	LINKS	`Index entries for sequences related to linear recurrences with constant coefficients` `Tanya Khovanova, Recursive Sequences`
	FORMULA	`a(n)={11[((3+sqrt(5))/2)^n - ((3-sqrt(5))/2)^n]-[((3+sqrt(5))/2)^(n-1) - ((3-sqrt(5))/2)^(n-1)]}/sqrt(5).` `G.f.(x)=(1+8x)/(1-3x+x^2).` `6Lucas(2n+1) - Fibonacci(2n+5).`
	CROSSREFS	`Cf. A055850.` `Sequence in context: A007790 A195857 A048773 * A006655 A018956 A018947` `Adjacent sequences: A056120 A056121 A056122 * A056124 A056125 A056126`
	KEYWORD	`easy,nonn`
	AUTHOR	`Barry E. Williams, Jul 06 2000`

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Last modified February 13 06:15 EST 2012. Contains 205438 sequences.