A172254 1 followed by period 4: repeat [-1, 3, -2, -1].

1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1, -1, 3, -2, -1

Offset

1,3

Links

Table of n, a(n) for n=1..77.

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

Formula

From Wesley Ivan Hurt, Jul 08 2016: (Start)

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

a(n) = a(n-4) for n>5.

a(n) = (5*I^(2*n) - 1 - (4-I)*I^(-n) - (4+I)*I^n)/4 for n>1. (End)

Maple

1, seq(op([-1, 3, -2, -1]), n=1..30); # Wesley Ivan Hurt, Jul 08 2016

Mathematica

Join[{1}, PadRight[{}, 100, {-1, 3, -2, -1}]] (* Wesley Ivan Hurt, Jul 08 2016 *)

Prog

(Magma) [1] cat &cat [[-1, 3, -2, -1]^^30]; // Wesley Ivan Hurt, Jul 08 2016
(PARI) Vec(x*(1-x+3*x^2-2*x^3-2*x^4)/(1-x^4) + O(x^99)) \\ Altug Alkan, Jul 08 2016

Crossrefs

Sequence in context: A231820 A010268 A181657 * A053542 A087284 A262311

Adjacent sequences: A172251 A172252 A172253 * A172255 A172256 A172257

Keyword

sign,less,easy

Author

L. Naing (lnaing.yangon_univ(AT)yahoo.in), Jan 29 2010

Extensions

Edited by Joerg Arndt, Sep 04 2011

Status

approved