A077851 Expansion of (1-x)^(-1)/(1 - 2*x - 2*x^3).

1, 3, 7, 17, 41, 97, 229, 541, 1277, 3013, 7109, 16773, 39573, 93365, 220277, 519701, 1226133, 2892821, 6825045, 16102357, 37990357, 89630805, 211466325, 498913365, 1177088341, 2777109333, 6552045397, 15458267477, 36470753621, 86045598037, 203007731029

Offset

0,2

Links

Table of n, a(n) for n=0..30.

Index entries for linear recurrences with constant coefficients, signature (3,-2,2,-2).

Maple

A052912 := proc(n) if n < 0 then 0; else coeftayl( 1/(1-2*x^3-2*x), x=0, n) ; end if; end proc:
A077851 := proc(n) 2*(2*A052912(n)+A052912(n-1)+A052912(n-2))-1 ;  %/3 ; end proc:
seq(A077851(n), n=0..15) ; # R. J. Mathar, Mar 28 2011

Prog

(PARI) Vec((1-x)^(-1)/(1-2*x-2*x^3)+O(x^99)) \\ Charles R Greathouse IV, Sep 27 2012

Crossrefs

Sequence in context: A192674 A272480 A131056 * A089737 A123335 A001333

Adjacent sequences: A077848 A077849 A077850 * A077852 A077853 A077854

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 17 2002

Status

approved