login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Table of n, a(n) for n=0..16.

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 A034667 A116149

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 Plewe, May 27 2007

More terms from Zerinvary Lajos, Jun 04 2007

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 24 11:12 EST 2018. Contains 299603 sequences. (Running on oeis4.)