A166249 a(n) = 2*a(n-1) - a(n-3) + 2*a(n-4) for n>3, a(0)=a(1)=1, a(2)=0, a(3)=2.

1, 1, 0, 2, 5, 12, 22, 43, 84, 170, 341, 684, 1366, 2731, 5460, 10922, 21845, 43692, 87382, 174763, 349524, 699050, 1398101, 2796204, 5592406, 11184811, 22369620, 44739242, 89478485, 178956972, 357913942, 715827883, 1431655764, 2863311530

Offset

0,4

Links

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

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

Formula

From R. J. Mathar, Nov 09 2009: (Start)

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

a(n) = A001045(n) + A010892(n+1). (End)

Mathematica

LinearRecurrence[{2, 0, -1, 2}, {1, 1, 0, 2}, 100] (* G. C. Greubel, May 08 2016 *)

Crossrefs

Sequence in context: A215183 A086734 A123647 * A326762 A116711 A247658

Adjacent sequences: A166246 A166247 A166248 * A166250 A166251 A166252

Keyword

nonn,easy

Author

Paul Curtz, Oct 10 2009

Extensions

Edited by N. J. A. Sloane, Oct 13 2009

Extended by R. J. Mathar, Nov 09 2009

Status

approved