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 A132419 Period 6: repeat [1, 1, -2, -1, -1, 2]. 2
 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Index entries for linear recurrences with constant coefficients, signature (0,0,-1). FORMULA a(n) = A061347(n+1) * (-1)^floor(n/3). a(n) = (1/6)*{(n mod 6)-[(n+1) mod 6]-[(n+3) mod 6]+[(n+4) mod 6]}. - Paolo P. Lava, Nov 19 2007 From Wesley Ivan Hurt, Jun 21 2016: (Start) G.f.: (1+x-2*x^2)/(1+x^3). a(n) + a(n-3) = 0 for n>2. a(n) = (5*cos(n*Pi/3) - 2*cos(n*Pi) - sqrt(3)*sin(n*Pi/3))/3. (End) MAPLE A132419:=n->[1, 1, -2, -1, -1, 2][(n mod 6)+1]: seq(A132419(n), n=0..100); # Wesley Ivan Hurt, Jun 21 2016 MATHEMATICA PadRight[{}, 100, {1, 1, -2, -1, -1, 2}] (* Wesley Ivan Hurt, Jun 21 2016 *) PROG (PARI) a(n)=[1, 1, -2, -1, -1, 2][n%6+1] \\ Charles R Greathouse IV, Jun 02 2011 (MAGMA) &cat [[1, 1, -2, -1, -1, 2]^^20]; // Wesley Ivan Hurt, Jun 21 2016 CROSSREFS Cf. A061347. Sequence in context: A131713 A100063 A057079 * A131556 A107751 A132367 Adjacent sequences:  A132416 A132417 A132418 * A132420 A132421 A132422 KEYWORD sign,easy,less AUTHOR Paul Curtz, Nov 13 2007 EXTENSIONS Comment changed to formula by Wesley Ivan Hurt, Jun 21 2016 STATUS approved

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Last modified May 29 03:06 EDT 2020. Contains 334696 sequences. (Running on oeis4.)