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A132677 Period 3: repeat [1, 2, -3]. 2
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 (list; graph; refs; listen; history; text; internal format)
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

a(n) = (1/3)*{-4*(n mod 3)+5*[(n+1) mod 3]-[(n+2) mod 3]}. - Paolo P. Lava, Nov 30 2007

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 A293207 A106590

Adjacent sequences:  A132674 A132675 A132676 * A132678 A132679 A132680

KEYWORD

sign,easy

AUTHOR

Paul Curtz, Nov 15 2007

STATUS

approved

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Last modified July 22 02:20 EDT 2019. Contains 325210 sequences. (Running on oeis4.)