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 A081922 Expansion of exp(4x)/sqrt(1-x^2). 1
 1, 4, 17, 76, 361, 1844, 10321, 64348, 453329, 3619684, 32666161, 329434604, 3677682937, 44901581716, 595567550321, 8505627039484, 130307878338721, 2126927187154628, 36912563369550289, 677277819029706124 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Binomial transform of A081921 Generally, if e.g.f. = exp(p*x)/sqrt(1-x^2), then a(n) ~ n^n * (exp(p)+(-1)^n*exp(-p)) / exp(n). - Vaclav Kotesovec, Feb 04 2014 LINKS FORMULA E.g.f. exp(4x)/sqrt(1-x^2). Conjecture: -a(n) +4*a(n-1) +(n-1)^2*a(n-2) -4*(n-1)*(n-2)*a(n-3)=0. - R. J. Mathar, Nov 09 2012 a(n) ~ n^n * (exp(4)+(-1)^n*exp(-4)) / exp(n). - Vaclav Kotesovec, Feb 04 2014 MATHEMATICA With[{nn=20}, CoefficientList[Series[Exp[4x]/Sqrt[1-x^2] , {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, May 07 2012 *) CROSSREFS Cf. A081919, A081920, A081921. Sequence in context: A239204 A005572 A202879 * A124325 A151248 A104455 Adjacent sequences:  A081919 A081920 A081921 * A081923 A081924 A081925 KEYWORD easy,nonn AUTHOR Paul Barry, Apr 01 2003 STATUS approved

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Last modified November 16 02:33 EST 2018. Contains 317252 sequences. (Running on oeis4.)