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A049686 a(n)=F(8n)/3, where F=A000045 (the Fibonacci sequence). 3
0, 7, 329, 15456, 726103, 34111385, 1602508992, 75283811239, 3536736619241, 166151337293088, 7805576116155895, 366695926122033977, 17226902951619441024, 809297742799991694151, 38019767008647990184073, 1786119751663655546957280, 83909608561183162716808087, 3941965482623944992143022809 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Indranil Ghosh, Table of n, a(n) for n = 0..597

Tanya Khovanova, Recursive Sequences

Index entries for linear recurrences with constant coefficients, signature (47,-1).

FORMULA

a(n) = 47*a(n-1) - a(n-2), n>1. a(0)=0, a(1)=7. G.f.: 7*x/(1-47*x+x^2).

a(n) = -(1/15)*sqrt(5)*[47/2-(21/2)*sqrt(5)]^n+(1/15)*[47/2+(21/2)*sqrt(5)]^n*sqrt(5), with n>=0. [Paolo P. Lava, Oct 07 2008]

a(n) = 7*A049668(n) . - R. J. Mathar, Oct 26 2015

EXAMPLE

a(2) = F(8 * 2) / 3 = F(16) / 3 = 987 / 3 = 329. - Indranil Ghosh, Feb 05 2017

PROG

(PARI) a(n) = fibonacci(8*n)/3; \\ Michel Marcus, Feb 05 2017

CROSSREFS

a(n) = A004187(2n).

Sequence in context: A109059 A002000 A092588 * A177019 A160432 A009587

Adjacent sequences:  A049683 A049684 A049685 * A049687 A049688 A049689

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

EXTENSIONS

Better description and more terms from Michael Somos

STATUS

approved

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Last modified May 23 23:53 EDT 2017. Contains 286937 sequences.