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A105812 Expansion of (1+x-x^2)/(1+x). 2
1, 0, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Row sums of number triangle A105810.

LINKS

Table of n, a(n) for n=0..77.

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

FORMULA

a(n)=-(-1)^n-binomial(1, n)+3*binomial(0, n)

a(n)=A033999(n-1), n>1. - R. J. Mathar, Aug 28 2008

MATHEMATICA

LinearRecurrence[{-1}, {1, 0, -1}, 78] (* Ray Chandler, Jul 30 2015 *)

PROG

(PARI) a(n)=if(n<2, 1-n, -(-1)^n) \\ Charles R Greathouse IV, Jun 06 2013

CROSSREFS

Sequence in context: A079054 A131695 A324113 * A134323 A060576 A261012

Adjacent sequences:  A105809 A105810 A105811 * A105813 A105814 A105815

KEYWORD

easy,sign

AUTHOR

Paul Barry, May 04 2005

STATUS

approved

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Last modified July 18 07:10 EDT 2019. Contains 325134 sequences. (Running on oeis4.)