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A122959 a(0) = 1, a(n) = (-1)^n*(2-2^(n-1)) for n>0. 1
1, -1, 0, 2, -6, 14, -30, 62, -126, 254, -510, 1022, -2046, 4094, -8190, 16382, -32766, 65534, -131070, 262142, -524286, 1048574, -2097150, 4194302, -8388606, 16777214, -33554430, 67108862, -134217726, 268435454, -536870910, 1073741822, -2147483646 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (-3, -2).

FORMULA

a(0) = 1, a(1) = -1, a(2) = 0, a(n) = (-3)*a(n-1)-2*a(n-2) for n>2 .

G.f. : (1+2*x-x^2)/(1+3*x+2*x^2).

MATHEMATICA

Join[{1}, LinearRecurrence[{-3, -2}, {-1, 0}, 50]] (* Vladimir Joseph Stephan Orlovsky, Feb 24 2012 *)

PROG

(PARI) Vec((1+2*x-x^2)/(1+3*x+2*x^2) + O(x^40)) \\ Michel Marcus, Nov 29 2015

CROSSREFS

Apart from signs, same as A000918.

Sequence in context: A260058 A228038 A122958 * A095121 A296965 A000918

Adjacent sequences:  A122956 A122957 A122958 * A122960 A122961 A122962

KEYWORD

sign

AUTHOR

Philippe Deléham, Oct 26 2006

EXTENSIONS

a(22) corrected by Vincenzo Librandi, Feb 24 2012

STATUS

approved

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Last modified July 22 08:27 EDT 2019. Contains 325216 sequences. (Running on oeis4.)