T(n,n), array T as in A047089.

Terms

a(0) =1a(1) =1a(2) =4a(3) =11a(4) =41a(5) =139a(6) =515a(7) =1871a(8) =7004a(9) =26191a(10) =99137a(11) =376300a(12) =1437105a(13) =5505203a(14) =21167781a(15) =81602665a(16) =315395985a(17) =1221558683a(18) =4740410605a(19) =18426590090a(20) =71736136773a(21) =279654633032