T(2n,n), array T as in A047040.

Terms

a(0) =1a(1) =1a(2) =5a(3) =23a(4) =136a(5) =833a(6) =4989a(7) =31065a(8) =196531a(9) =1241950a(10) =7930155a(11) =51007263a(12) =328816452a(13) =2128751494a(14) =13833853223a(15) =90098821854a(16) =588220949445