A132677 Period 3: repeat [1, 2, -3].

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

Offset

0,2

Comments

a(n) is proportional to its 6n-th differences.

Nonsimple continued fraction expansion of 1+sqrt(2/5) = 1.63245553... (see A010494). - R. J. Mathar, Mar 08 2012

Links

Table of n, a(n) for n=0..98.

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

Formula

G.f.: (1+3*x)/(1+x+x^2). - Jaume Oliver Lafont, Mar 24 2009

a(n) = cos(2*Pi*n/3) + 5*sin(2*Pi*n/3)/sqrt(3). - R. J. Mathar, Oct 08 2011

a(n) + a(n-1) + a(n-2) = 0 for n > 1, a(n) = a(n-3) for n > 2. - Wesley Ivan Hurt, Jul 01 2016

Maple

seq(op([1, 2, -3]), n=0..50); # Wesley Ivan Hurt, Jul 01 2016

Mathematica

PadRight[{}, 100, {1, 2, -3}] (* Wesley Ivan Hurt, Jul 01 2016 *)

Prog

(PARI) a(n)=[1, 2, -3][1+n%3] \\ Jaume Oliver Lafont, Mar 24 2009
(Magma) &cat [[1, 2, -3]^^30]; // Wesley Ivan Hurt, Jul 01 2016

Crossrefs

Cf. A000748, A010494, A049347, A101544.

Sequence in context: A179542 A082846 A117373 * A010882 A343638 A293207

Adjacent sequences: A132674 A132675 A132676 * A132678 A132679 A132680

Keyword

sign,easy

Author

Paul Curtz, Nov 15 2007

Status

approved