T(2n,n), array T as in A047120.

Terms

a(0) =1a(1) =1a(2) =6a(3) =28a(4) =166a(5) =971a(6) =5937a(7) =36736a(8) =230363a(9) =1458037a(10) =9292357a(11) =59576614a(12) =383721187a(13) =2481397399a(14) =16099317872a(15) =104753149406a(16) =683279530195