%I #6 Jul 28 2022 03:52:27
%S 0,0,1,3,12,42,156,570,2124,7926,29844,112812,428712,1635108,6259236,
%T 24031260,92517180,357019224,1380671532,5349496152,20762603724,
%U 80709201504,314178212928,1224576411084,4778651920092,18667769062044
%N a(n) = (1/2)*T(2n,n+1), where T is given by A048113.
%Y Cf. A048113.
%K nonn
%O 1,4
%A _Clark Kimberling_