A200563 Expansion of -2*x*(1+4*x) / ((2*x-1)*(4*x^2+3*x+1)).

2, 6, -2, 30, 14, 30, 238, -66, 782, 990, 46, 8190, -178, 16926, 48238, -15810, 247694, 106590, 262318, 1932414, -555058, 6518430, 7830766, 765630, 67043342, -2865954, 143077678, 387537150, -124309426, 2044005150, 807673198, 2285861694, 15681525902, -4648416930

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (-1,2,8).

Formula

a(n) = -a(n-1) +2*a(n-2) +8*a(n-3).

a(n) = (6*4^n+r^(n+1)+(16/r)^(n+1))/(7*2^n), where r=-3-sqrt(-7). - Bruno Berselli, Dec 12 2011

Mathematica

LinearRecurrence[{-1, 2, 8}, {2, 6, -2}, 34] (* Bruno Berselli, Dec 12 2011 *)

Prog

(Maxima) makelist(expand((6*4^n+(-3-sqrt(-7))^(n+1)+(-3+sqrt(-7))^(n+1))/(7*2^n)), n, 1, 34); /* Bruno Berselli, Dec 12 2011 */
(Magma) I:=[2, 6, -2]; [n le 3 select I[n] else -Self(n-1)+2*Self(n-2)+8*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jul 12 2012

Crossrefs

Sequence in context: A346093 A345284 A375250 * A284577 A122018 A363395

Adjacent sequences: A200560 A200561 A200562 * A200564 A200565 A200566

Keyword

sign,easy

Author

Krishnamurthy Balasubraniam, Nov 19 2011

Extensions

Definition from R. J. Mathar, Nov 19 2011

Status

approved