A095795 a(0)=2, a(1)=5, a(n+2) = a(n+1) + (-1)^n a(n).

2, 5, 7, 2, 9, 7, 16, 9, 25, 16, 41, 25, 66, 41, 107, 66, 173, 107, 280, 173, 453, 280, 733, 453, 1186, 733, 1919, 1186, 3105, 1919, 5024, 3105, 8129, 5024, 13153, 8129, 21282, 13153, 34435, 21282, 55717, 34435, 90152, 55717, 145869, 90152, 236021, 145869

Offset

0,1

Comments

Alternate terms form a Lucas sequence.

Specifically, a(2n) = A022113(n). - Jonathan Vos Post, Nov 16 2005

Links

Table of n, a(n) for n=0..47.

Eric Weisstein's World of Mathematics, Lucas Sequence.

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

Formula

a(n) = a(n-2) + a(n-4). G.f.: (3*x^3-5*x^2-5*x-2) / (x^4+x^2-1). - Colin Barker, Oct 18 2013

Mathematica

CoefficientList[Series[(3*x^3 - 5*x^2 - 5*x - 2)/(x^4 + x^2 - 1), {x, 0, 50}], x] (* Wesley Ivan Hurt, Jan 21 2017 *)

Crossrefs

Cf. A022113.

Sequence in context: A101245 A004576 A093200 * A088531 A291756 A286463

Adjacent sequences: A095792 A095793 A095794 * A095796 A095797 A095798

Keyword

nonn,easy

Author

Gary W. Adamson, Jun 06 2004

Extensions

Edited by Don Reble, Nov 15 2005

Missing terms inserted and more terms added by Colin Barker, Oct 18 2013

Status

approved