T(n,n-1), array T as in A047089.

Terms

a(0) =1a(1) =2a(2) =4a(3) =19a(4) =60a(5) =237a(6) =850a(7) =3252a(8) =12168a(9) =46497a(10) =177052a(11) =679745a(12) =2612226a(13) =10079515a(14) =38961906a(15) =150982379a(16) =586067980a(17) =2278999145a(18) =8874984360a(19) =34609160383a(20) =135125659144a(21) =528166347564