T(n,n-1), array T as in A047150.

Terms

a(0) =1a(1) =3a(2) =8a(3) =27a(4) =90a(5) =320a(6) =1170a(7) =4243a(8) =15700a(9) =58415a(10) =219547a(11) =831826a(12) =3160495a(13) =12062741a(14) =46187360a(15) =177436402a(16) =683765925a(17) =2640846975a(18) =10221025773a(19) =39630943814a(20) =153924315307a(21) =598776610777