T(n,n-1), array T as in A047100.

Terms

a(0) =1a(1) =1a(2) =5a(3) =16a(4) =58a(5) =220a(6) =821a(7) =3090a(8) =11743a(9) =44792a(10) =171495a(11) =659051a(12) =2540116a(13) =9814642a(14) =38007320a(15) =147472450a(16) =573200298a(17) =2231386904a(18) =8698569320a(19) =33952074197a(20) =132672190652a(21) =518973027214