A119837 a(n)=(2n)!/n!-(2n)!/(n-1)!.

1, 0, -12, -240, -5040, -120960, -3326400, -103783680, -3632428800, -141145804800, -6033983155200, -281585880576000, -14248245557145600, -777177030389760000, -45464856277800960000, -2839804869044183040000, -188644180586506444800000

Offset

0,3

Comments

Row sums of number triangle A119836.

Links

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

Formula

a(n)=A001813(n)-2*A001814(n).

Mathematica

f[n_]:=Module[{n2f=(2n)!}, n2f/n!-n2f/(n-1)!]; f/@Range[0, 20]  (* Harvey P. Dale, Feb 13 2011 *)

Crossrefs

Sequence in context: A009052 A213449 A012303 * A012538 A006588 A009150

Adjacent sequences: A119834 A119835 A119836 * A119838 A119839 A119840

Keyword

easy,sign

Author

Paul Barry, May 25 2006

Status

approved