A108413 Expansion of (1+x+5x^2+2x^3) / (1-4x^2+x^4).

1, 1, 1, -2, -5, 7, 19, -26, -71, 97, 265, -362, -989, 1351, 3691, -5042, -13775, 18817, 51409, -70226, -191861, 262087, 716035, -978122, -2672279, 3650401, 9973081, -13623482, -37220045, 50843527, 138907099, -189750626, -518408351, 708158977, 1934726305

Offset

0,4

Links

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,-4,0,-1).

Formula

a(0)=a(1)=a(2)=1, a(n)*a(n+3) - a(n+1)*a(n+2) = -3.

a(n) = 4*a(n-2) + a(n-4) for n>3. - Colin Barker, Sep 07 2017

Prog

(PARI) Vec((1 + x + 5*x^2 + 2*x^3) / (1 + 4*x^2 + x^4) + O(x^40)) \\ Colin Barker, Sep 07 2017

Crossrefs

Unsigned values are in A002531.

Sequence in context: A045359 A042809 A002531 * A042449 A046115 A267481

Adjacent sequences: A108410 A108411 A108412 * A108414 A108415 A108416

Keyword

sign,easy

Author

Ralf Stephan, Jun 05 2005

Status

approved