T(n,n+2), array T as in A004730.

Terms

a(0) =1a(1) =3a(2) =10a(3) =35a(4) =125a(5) =455a(6) =1680a(7) =6270a(8) =23591a(9) =89335a(10) =340076a(11) =1300234a(12) =4989504a(13) =19206500a(14) =74132230a(15) =286802444a(16) =1111864311a(17) =4318284037a(18) =16798674426a(19) =65444081290a(20) =255290775209a(21) =997047334415