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A156283 Period 6: repeat [1, 2, 4, -4, -2, -1]. 2
1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2, 4, -4, -2, -1, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..73.

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

FORMULA

a(n) == A141425(n) (mod 9). - Paul Curtz, Feb 08 2009

a(n) = ( (2*A141425(n)) mod 9) - A141425(n). - Paul Curtz, Feb 08 2009

a(n) = (1/6)*{-2*(n mod 6)-[(n+1) mod 6]-2*[(n+2) mod 6]+8*[(n+3) mod 6]-2*[(n+4) mod 6]-[(n+5) mod 6]}. [Paolo P. Lava, Feb 13 2009]

G.f.: (1+x^4+3*x^3+7*x^2+3*x)/( (x+1)*(x^2-x+1)*(x^2+x+1) ). [Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009]

From Wesley Ivan Hurt, Jun 23 2016: (Start)

a(n) + a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5) = 0 for n>4.

a(n) = cos(n*Pi) + 2*sqrt(3)*cos(n*Pi/6)*sin(n*Pi/6) - sqrt(3)*cos(n*Pi/2)*sin(n*Pi/6) + 3*sin(n*Pi/6)*sin(n*Pi/2). (End)

MAPLE

A156283:=n->[1, 2, 4, -4, -2, -1][(n mod 6)+1]: seq(A156283(n), n=0..100); # Wesley Ivan Hurt, Jun 23 2016

MATHEMATICA

PadRight[{}, 80, {1, 2, 4, -4, -2, -1}] (* or *) LinearRecurrence[{-1, -1, -1, -1, -1}, {1, 2, 4, -4, -2}, 80] (* Harvey P. Dale, May 29 2013 *)

PROG

(MAGMA) &cat [[1, 2, 4, -4, -2, -1]^^20]; // Wesley Ivan Hurt, Jun 23 2016

CROSSREFS

Cf. A141425.

Sequence in context: A108620 A070512 A156346 * A126123 A285349 A256066

Adjacent sequences:  A156280 A156281 A156282 * A156284 A156285 A156286

KEYWORD

sign,easy

AUTHOR

Paul Curtz, Feb 07 2009

STATUS

approved

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Last modified May 8 20:32 EDT 2021. Contains 343668 sequences. (Running on oeis4.)