A121892 Row sums of triangle in A066094.

1, 2, 4, 24, 192, 1920, 23040, 322560, 5160960, 92897280, 1857945600, 40874803200, 980995276800

Offset: 0

Author

Philippe Deléham, Sep 01 2006

Keywords

• nonn

Crossrefs

Cf. A000165, A002866, A032107, A066094.

Formula

a(0)=1, a(1)=2, a(n)=A000165(n)/2 for n>1.

a(n)=A032107(n), n>0. - R. J. Mathar, Jun 05 2008

G.f.: 1 + x + x/Q(0), where Q(k) = 1 - 4*x*(2*k+1) - 4*x^2*(2*k+1)*(2*k+2)/( 1 - 4*x*(2*k+2) - 4*x^2*(2*k+2)*(2*k+3)/Q(k+1) ) ; (continued fraction). - Sergei N. Gladkovskii, Sep 23 2013

a(n) = A002866(n) for n>=2. - Alois P. Heinz, Nov 17 2024