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

Author

Paul Barry, May 25 2006

Keywords

• easy
• sign

Comments

Row sums of number triangle A119836.

Programs

Mathematica

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

Formula

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