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A117374 Expansion of (1-3x)/(1-x^2+x^3). 2
1, -3, 1, -4, 4, -5, 8, -9, 13, -17, 22, -30, 39, -52, 69, -91, 121, -160, 212, -281, 372, -493, 653, -865, 1146, -1518, 2011, -2664, 3529, -4675, 6193, -8204, 10868, -14397, 19072, -25265, 33469 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Diagonal sums of number triangle A117372.

LINKS

Table of n, a(n) for n=0..36.

Index entries for linear recurrences with constant coefficients, signature (0,1,-1).

FORMULA

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

CROSSREFS

Sequence in context: A260502 A014388 A186693 * A202142 A021322 A277129

Adjacent sequences:  A117371 A117372 A117373 * A117375 A117376 A117377

KEYWORD

easy,sign

AUTHOR

Paul Barry, Mar 10 2006

STATUS

approved

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Last modified December 14 14:20 EST 2019. Contains 329979 sequences. (Running on oeis4.)