%I #4 Mar 30 2012 18:56:06
%S 1,4,20,104,560,3080,17199,97120,553146,3171860,18288127,105922544,
%T 615820400,3591858480,21008159700,123169357728,723659556026,
%U 4259672761560,25115352874780,148302374872080,876876653336922,5191051724957736
%N a(n) = T(2n,n-1), where T is the array in A026300.
%K nonn
%O 1,2
%A _Clark Kimberling_