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

0,3

Comments

Every term is an integer.

Links

Table of n, a(n) for n=0..13.

Formula

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

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 *)

Crossrefs

Cf. A000254.

Sequence in context: A134262 A240289 A001536 * A178689 A095983 A059166

Adjacent sequences: A114447 A114448 A114449 * A114451 A114452 A114453

Keyword

nonn

Author

Leroy Quet, Feb 14 2006

Extensions

More terms from Emeric Deutsch, May 15 2006

Status

approved