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A135261 a(n) = 3*A131090(n) - A131090(n+1). 1
-1, 3, -1, 2, -1, 5, 6, 17, 27, 58, 111, 229, 454, 913, 1819, 3642, 7279, 14565, 29126, 58257, 116507, 233018, 466031, 932069, 1864134, 3728273, 7456539, 14913082, 29826159, 59652325, 119304646, 238609297, 477218587, 954437178, 1908874351, 3817748709, 7635497414 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (2,0,-1,2).

FORMULA

A131090(n) - a(n) = A131556(n).

O.g.f.: (1-x)^2*(1-3x)/((2x-1)(1+x)(x^2-x+1)) . - R. J. Mathar, Jul 22 2008

a(n) = 2*a(n-1) - a(n-3) + 2*a(n-4). - G. C. Greubel, Oct 07 2016

MATHEMATICA

LinearRecurrence[{2, 0, -1, 2}, {-1, 3, -1, 2}, 25] (* G. C. Greubel, Oct 07 2016 *)

CROSSREFS

Sequence in context: A285121 A295935 A318323 * A102774 A131918 A010123

Adjacent sequences:  A135258 A135259 A135260 * A135262 A135263 A135264

KEYWORD

sign

AUTHOR

Paul Curtz, Dec 01 2007

EXTENSIONS

Edited and extended by R. J. Mathar, Jul 22 2008

STATUS

approved

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Last modified October 18 00:07 EDT 2019. Contains 328135 sequences. (Running on oeis4.)