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 A092956 a(n) = (2*n+2)!/((n+2)*n!). 7
 1, 8, 90, 1344, 25200, 570240, 15135120, 461260800, 15878903040, 609493248000, 25812039052800, 1195656969830400, 60138698780160000, 3264143527636992000, 190165504623494400000, 11836497605427855360000, 783921372659482337280000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA a(n) = sum(Gamma(n+1+k)/Gamma(k), k=1..n+1). [Bruno Berselli, Mar 06 2013] Let E(x)=sum(n>=0, a(n)*x^(2*n)/n!  ), then E(x) = 2- E(0,x), where E(k,x) = 1 - x^2*(k+1)/( x^2*(k+1) + (k + 1 -x^2)*(k + 2 -x^2)/E(k+1,x) ); (continued fraction). - Sergei N. Gladkovskii, Oct 21 2013 a(n) = A092582(2n+2,n+1). - Alois P. Heinz, Jun 19 2017 MAPLE seq((2*n+2)!/(n+2)/n!, n=0..17); # Emeric Deutsch a:=n->sum(mul (j-k+n, j=1..n), k=1..n): seq(a(n), n=1..17); # Zerinvary Lajos, Jun 04 2007 MATHEMATICA Table[(2 n + 2)!/((n + 2) n!), {n, 0, 16}] (* Bruno Berselli, Mar 06 2013 *) PROG (Maxima) A092956(n):=(2*n+2)!/((n+2)*n!)\$ makelist(A092956(n), n, 0, 30); /* Martin Ettl, Nov 05 2012 */ CROSSREFS Row sums of A105725. Cf. A092582. Sequence in context: A056784 A166769 A187667 * A295623 A319174 A034667 Adjacent sequences:  A092953 A092954 A092955 * A092957 A092958 A092959 KEYWORD easy,nonn AUTHOR Amarnath Murthy, Mar 25 2004 EXTENSIONS More terms from Emeric Deutsch, Apr 18 2005 Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 27 2007 More terms from Zerinvary Lajos, Jun 04 2007 STATUS approved

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Last modified October 17 22:48 EDT 2018. Contains 316297 sequences. (Running on oeis4.)