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A077990 Expansion of 1/(1+2*x+x^2-x^3). +0
3
1, -2, 3, -3, 1, 4, -12, 21, -26, 19, 9, -63, 136, -200, 201, -66, -269, 805, -1407, 1740, -1268, -611, 4230, -9117, 13393, -13439, 4368, 18096, -53999, 94270, -116445, 84621, 41473, -284012, 611172, -896859, 898534, -289037, -1217319, 3622209, -6316136, 7792744, -5647143, -2814594 (list; graph; listen)
OFFSET

0,2

FORMULA

G.f.: 1/((1+x)^2-x^3); a(n)=sum{k=0..n+4, (-1)^(n-k-1)*C(n+3, k)*sum{j=0..floor(k/3), C(k-2j, j)}}. - Paul Barry (pbarry(AT)wit.ie), May 10 2005

CROSSREFS

Adjacent sequences: A077987 A077988 A077989 this_sequence A077991 A077992 A077993

Sequence in context: A076780 A089283 A077941 this_sequence A085667 A035516 A120428

KEYWORD

sign

AUTHOR

njas, Nov 17 2002

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Last modified October 5 16:50 EDT 2008. Contains 144613 sequences.


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