A114450 a(n)=(2n)!*(sum{k=1...2n}1/k)/(2n+1).

0, 1, 10, 252, 12176, 966240, 114341760, 18897709824, 4160840140800, 1177736213606400, 416807049369600000, 180368555623280640000, 93711488655948742656000, 57572391079539343687680000

Offset: 0

Author

Leroy Quet, Feb 14 2006

Keywords

• nonn

Comments

Every term is an integer.

Crossrefs

Cf. A000254.

Programs

Maple

seq((2*n)!*(sum(1/k,k=1..2*n))/(2*n+1),n=0..15); - Emeric Deutsch, May 15 2006

Mathematica

Table[(2n)! Sum[1/k,{k,2n}]/(2n+1),{n,0,20}] (* Harvey P. Dale, Aug 27 2012 *)

Formula

a(n) = A000254(2n)/(2n+1)

Extensions

More terms from Emeric Deutsch, May 15 2006