T(n,n+1), array T as in A047100.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =73a(5) =261a(6) =957a(7) =3547a(8) =13267a(9) =50027a(10) =189780a(11) =723456a(12) =2769333a(13) =10637790a(14) =40984228a(15) =158306891a(16) =612856611a(17) =2377260192a(18) =9237543329a(19) =35951472496a(20) =140116098727a(21) =546778366195