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A022087 Fibonacci sequence beginning 0 4. 7
0, 4, 4, 8, 12, 20, 32, 52, 84, 136, 220, 356, 576, 932, 1508, 2440, 3948, 6388, 10336, 16724, 27060, 43784, 70844, 114628, 185472, 300100, 485572, 785672, 1271244, 2056916, 3328160, 5385076, 8713236, 14098312, 22811548, 36909860, 59721408, 96631268 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

A. T. Benjamin and J. J. Quinn, Proofs that really count: the art of combinatorial proof, M.A.A. 2003, id. 18.

LINKS

Table of n, a(n) for n=0..37.

Tanya Khovanova, Recursive Sequences

Index entries for sequences related to linear recurrences with constant coefficients, signature (1,1).

FORMULA

a(n) = round( (8phi-4)/5 phi^n) (works for n>2) - Thomas Baruchel, Sep 08 2004

a(n) = 4F(n) = F(n-2) + F(n) + F(n+2), with F(n) = A000045(n).

a(n) = A119457(n+2,n-1) for n>1. - Reinhard Zumkeller, May 20 2006

G.f.: 4x/(1-x-x^2). [From Philippe DELEHAM, Nov 19 2008]

a(n)=F(n+9)-17F(n+3), n>=0, F(n)=A000045. [From Manuel Valdivia, Dec 15 2009]

MAPLE

a := n-> (Matrix([[4, 0]]). Matrix([[1, 1], [1, 0]])^n)[1, 2]: seq (a(n), n=0..32); [From Alois P. Heinz, Aug 17 2008]

MATHEMATICA

a={}; b=0; c=4; AppendTo[a, b]; AppendTo[a, c]; Do[b=b+c; AppendTo[a, b]; c=b+c; AppendTo[a, c], {n, 1, 9, 1}]; a (Vladimir Orlovsky, Jul 22 2008)

PROG

(PARI) a(n)=4*fibonacci(n) \\ Charles R Greathouse IV, Jun 05, 2011

CROSSREFS

Sequence in context: A194697 A194696 A002368 * A095294 A190100 A030168

Adjacent sequences:  A022084 A022085 A022086 * A022088 A022089 A022090

KEYWORD

nonn,easy,changed

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified May 24 01:37 EDT 2013. Contains 225613 sequences.