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A122434 Expansion of (1+x)^3/(1+x+x^2). 1
1, 2, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0, -1, 1, 0 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Row sums of number triangle A122433. Binomial transform is A077859.

FORMULA

a(n)=2*sqrt(3)*cos(2*pi*n/3+pi/6)/3+C(1,n)+C(0,n)

a(n) = -A049347(n) if n>=2 . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 08 2008

CROSSREFS

Sequence in context: A116377 A131964 A065339 * A141571 A164067 A113706

Adjacent sequences:  A122431 A122432 A122433 * A122435 A122436 A122437

KEYWORD

easy,sign

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Sep 04 2006

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Last modified February 15 20:26 EST 2012. Contains 205852 sequences.