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 A124342 Expansion of (1+x)/(1+2x-2x^3). 1
 1, -1, 2, -2, 2, 0, -4, 12, -24, 40, -56, 64, -48, -16, 160, -416, 800, -1280, 1728, -1856, 1152, 1152, -6016, 14336, -26368, 40704, -52736, 52736, -24064, -57344, 220160, -488448, 862208, -1284096, 1591296, -1458176, 348160 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Diagonal sums of A124341. Binomial transform has g.f. (1-x)/(1-x-x^2-x^3). LINKS Index entries for linear recurrences with constant coefficients, signature (-2,0,2). FORMULA a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, (-1)^(n-k-j)*C(n-k,j)*C(k,j-k)}} a(n) = (-1)^(n+1)*A073358(n+1). - R. J. Mathar, Feb 04 2014 a(n) = A077988(n-1)+A077988(n). - R. J. Mathar, Jan 25 2016 CROSSREFS Sequence in context: A151930 A084203 A073358 * A082835 A104241 A011139 Adjacent sequences:  A124339 A124340 A124341 * A124343 A124344 A124345 KEYWORD easy,sign AUTHOR Paul Barry, Oct 26 2006 STATUS approved

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Last modified August 19 05:11 EDT 2019. Contains 326109 sequences. (Running on oeis4.)