T(2n,n), array T as in A047030.

Terms

a(0) =1a(1) =1a(2) =4a(3) =22a(4) =126a(5) =751a(6) =4595a(7) =28514a(8) =179277a(9) =1136405a(10) =7256229a(11) =46583010a(12) =300438175a(13) =1944986187a(14) =12632217312a(15) =82269089182a(16) =537071072123