0,2

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

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

G.f.: (1 + 2*x - x^2 - x^5) / (1 - x^2)^2.

From Colin Barker, Mar 04 2017: (Start)

a(n) = 2*a(n-2) - a(n-4) for n>3.

a(n) = 1 for n>1 and even.

a(n) = (n+5) / 2 for n>1 and odd.

(End)

(PARI) Vec((1 + 2*x - x^2 - x^5) / ((1 - x)^2*(1 + x)^2) + O(x^100)) \\ Colin Barker, Mar 04 2017

Cf. A282737.

A152271 and A133622 are very similar sequences.

Sequence in context: A284652 A261242 A088296 * A093890 A325609 A006306

Adjacent sequences: A282735 A282736 A282737 * A282739 A282740 A282741

nonn,easy

N. J. A. Sloane, Mar 04 2017

approved