A063758 a(0)=1, a(n) = 2*Fibonacci(n+4) - 6.

1, 4, 10, 20, 36, 62, 104, 172, 282, 460, 748, 1214, 1968, 3188, 5162, 8356, 13524, 21886, 35416, 57308, 92730, 150044, 242780, 392830, 635616, 1028452, 1664074, 2692532, 4356612, 7049150, 11405768, 18454924, 29860698, 48315628, 78176332, 126491966

Offset

0,2

References

P. de la Harpe, Topics in Geometric Group Theory, Univ. Chicago Press, 2000, p. 158.

Links

Harry J. Smith, Table of n, a(n) for n = 0..500

Index entries for linear recurrences with constant coefficients, signature (2, 0, -1).

Formula

G.f.: (1+2*x+2*x^2+x^3)/((1-x-x^2)*(1-x)).

Maple

seq(`if`(n=0, 1, 2*combinat[fibonacci](n+4)-6), n=0..35); # Nathaniel Johnston, Jun 28 2011

Mathematica

Table[If[n == 0, 1, 2*Fibonacci[n + 4] - 6], {n, 0, 100}] (* Vladimir Joseph Stephan Orlovsky, Jun 28 2011 *)

Prog

(PARI) a(n) = { if(n==0, 1, 2*fibonacci(n+4) - 6) } \\ Harry J. Smith, Aug 29 2009

Crossrefs

Sequence in context: A264924 A008059 A145132 * A131924 A143982 A000749

Adjacent sequences: A063755 A063756 A063757 * A063759 A063760 A063761

Keyword

nonn,easy

Author

N. J. A. Sloane, Aug 14 2001

Status

approved