T(n,n+1), array T as in A047110.

Terms

a(0) =1a(1) =2a(2) =5a(3) =19a(4) =62a(5) =206a(6) =771a(7) =2787a(8) =10075a(9) =37936a(10) =142127a(11) =532438a(12) =2025548a(13) =7717368a(14) =29431808a(15) =112981883a(16) =434717592a(17) =1674938528a(18) =6474529712a(19) =25076461217a(20) =97253412518a(21) =377901902151