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 A166078 Expansion of (3(1-x)-sqrt(1+6x-7x^2))/(2(1-x)(1-2x)). 1
 1, 0, 2, -6, 30, -150, 806, -4494, 25822, -151782, 908502, -5518590, 33933774, -210814422, 1321230150, -8343458286, 53037407166, -339111023046, 2179407749558, -14071216784862, 91225811704750, -593639364476598 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS First column of inverse of Riordan array ((1+x)/(1+x+2x^2),x(1+2x)/(1+x+2x^2)). Hankel transform is A002416. Binomial transform of A114191. REFERENCES A. Hora, N. Obata, Quantum Probability and Spectral Analysis of Graphs, Springer, 2007, p. 122 LINKS G. C. Greubel, Table of n, a(n) for n = 0..500 FORMULA G.f.: 1/(1-x+x*c(-2x/(1-x))), c(x) the g.f. of A000108. G.f.: 1/(1-2x^2/(1-3x-4x^2/(1-3x-4x^2/(1-3x-4x^2/(1-... (continued fraction). Conjecture: n*a(n) + 2*(2*n-5)*a(n-1) + (34-19*n)*a(n-2) + 14*(n-2)*a(n-3)=0. - R. J. Mathar, Nov 14 2011 MATHEMATICA CoefficientList[Series[(3 (1 - x) - Sqrt[1 + 6 x - 7 x^2])/(2 (1 - x) (1 - 2 x)), {x, 0, 50}], x](* G. C. Greubel, Apr 24 2016 *) CROSSREFS Sequence in context: A055695 A113593 A122763 * A319365 A319104 A192446 Adjacent sequences:  A166075 A166076 A166077 * A166079 A166080 A166081 KEYWORD easy,sign AUTHOR Paul Barry, Oct 06 2009 STATUS approved

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Last modified January 17 23:15 EST 2019. Contains 319251 sequences. (Running on oeis4.)