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A130815 Period 6: repeat [1, 5, 4, -1, -5, -4]. 6
1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4, 1, 5, 4, -1, -5, -4 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Continued fraction expansion of (5+sqrt(11))/7 = 1.1880892557650... - R. J. Mathar, Mar 08 2012

LINKS

Table of n, a(n) for n=0..71.

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

FORMULA

Also binomial transform of 1, 4, -5.

a(n) = (1/6)*{-5*(n mod 6)-[(n+1) mod 6]+4*[(n+2) mod 6]+5*[(n+3) mod 6]+[(n+4) mod 6]-4*[(n+5) mod 6]}. - Paolo P. Lava, Aug 28 2007

From R. J. Mathar, Oct 30 2008: (Start)

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

a(n) = A010892(n) + 4*A010892(n-1). (End)

From Wesley Ivan Hurt, Jun 17 2016: (Start)

a(n) = a(n-1) - a(n-2) for n>1.

a(n) = cos(n*Pi/3) + 3*sqrt(3)*sin(n*Pi/3). (End)

MAPLE

A130815:=n->cos(n*Pi/3)+3*sqrt(3)*sin(n*Pi/3): seq(A130815(n), n=0..100); # Wesley Ivan Hurt, Jun 17 2016

MATHEMATICA

Flatten[Table[{1, 5, 4, -1, -5, -4}, {20}]] (* Wesley Ivan Hurt, Jun 17 2016 *)

PROG

(PARI) a(n)=[1, 5, 4, -1, -5, -4][n%6+1] \\ Charles R Greathouse IV, Jun 02 2011

(MAGMA) &cat[[1, 5, 4, -1, -5, -4]: n in [0..20]]; // Wesley Ivan Hurt, Jun 17 2016

CROSSREFS

Cf. A010892.

Sequence in context: A198352 A113011 A028875 * A084129 A011503 A296498

Adjacent sequences:  A130812 A130813 A130814 * A130816 A130817 A130818

KEYWORD

sign,easy,less

AUTHOR

Paul Curtz, Jul 16 2007

EXTENSIONS

Edited by N. J. A. Sloane, Sep 15 2007

STATUS

approved

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Last modified April 10 02:39 EDT 2020. Contains 333392 sequences. (Running on oeis4.)