%I #4 Mar 30 2012 18:56:54
%S 1,2,6,18,60,204,720,2580,9408,34668,129024,483672,1824768,6919752,
%T 26357976,100778472,386591304,1487221056,5735785176,22170562656,
%U 85866332760,333151068528,1294658562912,5038469947992,19634243736168
%N a(n)=(1/2)*T(2n,n), where T is given by A048113.
%K nonn
%O 2,2
%A _Clark Kimberling_