T(2n,n), array T as in A047150.

Terms

a(0) =1a(1) =3a(2) =13a(3) =72a(4) =417a(5) =2509a(6) =15438a(7) =96310a(8) =607231a(9) =3859594a(10) =24689329a(11) =158756701a(12) =1025210362a(13) =6644336882a(14) =43193144567a(15) =281525730152