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 A274634 a(n) = n!*A003436(n). 3
 0, 2, 24, 744, 35160, 2394720, 222712560, 27154350720, 4205374225920, 806700010233600, 187793061031699200, 52162131258836121600, 17043501717850146739200, 6471785359791584459827200, 2826261760629911644744704000, 1406604814631643298586923008000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..100 FORMULA a(n) ~ 2*sqrt(Pi*n)*2^n*n^(2*n)/exp(2*n+1). - Ilya Gutkovskiy, Aug 18 2016 MATHEMATICA a[n_]:= n! (2 n - 1)!! Hypergeometric1F1[-n, 1 - 2 n, - 2]; a[1] = 0; Table[a[n], {n, 1, 20}] (* Vincenzo Librandi, Aug 18 2016 *) CROSSREFS Cf. A003436. Sequence in context: A177771 A009396 A338188 * A292694 A012128 A099704 Adjacent sequences: A274631 A274632 A274633 * A274635 A274636 A274637 KEYWORD nonn AUTHOR N. J. A. Sloane, Jul 08 2016 STATUS approved

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Last modified September 17 23:36 EDT 2024. Contains 375991 sequences. (Running on oeis4.)