A178115 a(n)=(-1)^C(n+1,2)*(F(n+1)*(1+(-1)^n)/2+F(n+2)*(1-(-1)^n)/2).

1, -2, -2, 5, 5, -13, -13, 34, 34, -89, -89, 233, 233, -610, -610, 1597, 1597, -4181, -4181, 10946, 10946, -28657, -28657, 75025, 75025, -196418, -196418, 514229, 514229, -1346269, -1346269, 3524578, 3524578, -9227465, -9227465, 24157817

Offset

0,2

Comments

Duplicated A001519 with alternating signs.

Hankel transform of A178113. Hankel transform of A178114.

Links

Table of n, a(n) for n=0..35.

Index entries for linear recurrences with constant coefficients, signature (0,-3,0,-1).

Formula

G.f.: (1-2x+x^2-x^3)/(1+3x^2+x^4).

|a(n)| = A094967(n+1). - R. J. Mathar, Dec 10 2010

Prog

(PARI) Vec((1-2*x+x^2-x^3)/(1+3*x^2+x^4) + O(x^50)) \\ Michel Marcus, Dec 03 2014

Crossrefs

Sequence in context: A368923 A338762 A364486 * A094967 A322111 A321395

Adjacent sequences: A178112 A178113 A178114 * A178116 A178117 A178118

Keyword

easy,sign

Author

Paul Barry, May 20 2010

Status

approved