|
|
A121892
|
|
Row sums of triangle in A066094.
|
|
0
|
|
|
1, 2, 4, 24, 192, 1920, 23040, 322560, 5160960, 92897280, 1857945600, 40874803200, 980995276800
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
a(0)=1, a(1)=2, a(n)=A000165(n)/2 for n>1.
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
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|