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 A116421 a(n) = 2^(n-1)*binomial(2n-1,n-1)^2. 1
 0, 1, 18, 400, 9800, 254016, 6830208, 188457984, 5300380800, 151289881600, 4369251780608, 127394382495744, 3743979352236032, 110768619888640000, 3295931587706880000, 98555678764852838400, 2959750227906986803200 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..100 FORMULA G.f.: 1+(K(32x)-1)/4 where K(k)=Elliptic_F(pi/2,k) is the complete Elliptic integral of the first kind; e.g.f.: BesselI(0, 2*sqrt(2)x)*BesselI(1, 2*sqrt(2)x)/sqrt(2); a(n) = 2^(n+1)*(binomial(2n,n)/4)^2 - 0^n/8. Conjecture: n^2*a(n) - (2*n-1)^2*a(n-1) = 0. - R. J. Mathar, Nov 16 2011 PROG (Magma) [2^(n-1)*Binomial(2*n-1, n-1)^2: n in [0..20]]; // Vincenzo Librandi, Nov 17 2011 CROSSREFS Cf. A060150. Sequence in context: A252888 A159647 A111454 * A298465 A260655 A318598 Adjacent sequences: A116418 A116419 A116420 * A116422 A116423 A116424 KEYWORD easy,nonn AUTHOR Paul Barry, Feb 14 2006 STATUS approved

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Last modified March 24 18:16 EDT 2023. Contains 361510 sequences. (Running on oeis4.)