OFFSET
0,2
FORMULA
a(n)=sum{k=0..n, C(n,k)*(floor(k/2)!)^2}; a(n)=sum{k=0..n, sum{j=0..n-k, C(n-k,j)C(k,j)j!^2}}; - Paul Barry, May 26 2007
CROSSREFS
KEYWORD
nonn
AUTHOR
Ralf Stephan, Oct 28 2004
STATUS
approved