T(n,n+2), array T as in A047120.

Terms

a(0) =1a(1) =3a(2) =10a(3) =35a(4) =127a(5) =467a(6) =1736a(7) =6510a(8) =24591a(9) =93427a(10) =356620a(11) =1366586a(12) =5254256a(13) =20259304a(14) =78309078a(15) =303346956a(16) =1177325247a(17) =4577098533a(18) =17821458618a(19) =69484705346a(20) =271251048911