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A119303 Expansion of (1-3x)/(1-x+2x^2-x^3). 1
1, -2, -4, 1, 7, 1, -12, -7, 18, 20, -23, -45, 21, 88, 1, -154, -68, 241, 223, -327, -532, 345, 1082, -140, -1959, -597, 3181, 2416, -4543, -6194, 5308, 13153, -3657, -24655, -4188, 41465, 25186, -61932, -70839, 78211, 157957 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Row sums of number triangle A119302.

FORMULA

a(n)=a(n-1)-2a(n-2)+a(n-3); a(n)=sum{k=0..n, (C(2k,n-k)+3*C(2k,n-k-1))(-1)^(n-k)}.

CROSSREFS

Sequence in context: A089087 A142146 A143350 * A105552 A112852 A121531

Adjacent sequences:  A119300 A119301 A119302 * A119304 A119305 A119306

KEYWORD

easy,sign

AUTHOR

Paul Barry (pbarry(AT)wit.ie), May 13 2006

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Last modified February 16 19:06 EST 2012. Contains 205945 sequences.