T(n,n+2), array T given by A047020.

Terms

a(0) =1a(1) =3a(2) =9a(3) =28a(4) =95a(5) =331a(6) =1169a(7) =4234a(8) =15533a(9) =57410a(10) =214396a(11) =806324a(12) =3046963a(13) =11575473a(14) =44163245a(15) =169039223a(16) =649096030a(17) =2499407973a(18) =9646255701a(19) =37309138495a(20) =144580572524a(21) =561217993364