A022325 a(n) = a(n-1) + a(n-2) + 1, with a(0) = 1 and a(1) = 11.

1, 11, 13, 25, 39, 65, 105, 171, 277, 449, 727, 1177, 1905, 3083, 4989, 8073, 13063, 21137, 34201, 55339, 89541, 144881, 234423, 379305, 613729, 993035, 1606765, 2599801, 4206567, 6806369, 11012937

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

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

Formula

From R. J. Mathar, Apr 07 2011: (Start)

G.f.: (1+9*x-9*x^2)/((1-x)*(1-x-x^2)).

a(n) = A022368(n) - 1. (End)

a(n) = 2*F(n+2) + 8*F(n) - 1, where F = A000045. - G. C. Greubel, Aug 25 2017

Mathematica

LinearRecurrence[{2, 0, -1}, {1, 11, 13}, 50] (* G. C. Greubel, Aug 25 2017 *)

Prog

(PARI) x='x+O('x^50); Vec((1+9*x-9*x^2)/((1-x)*(1-x-x^2))) \\ G. C. Greubel, Aug 25 2017

Crossrefs

Sequence in context: A277048 A275598 A090433 * A295340 A153055 A146915

Adjacent sequences: A022322 A022323 A022324 * A022326 A022327 A022328

Keyword

nonn

Author

N. J. A. Sloane

Status

approved