Triangle read by rows: T(n,k) = Sum_{i=k..n} C(i-1,i-k)*C(i,k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =1a(7) =6a(8) =7a(9) =1a(10) =1a(11) =10a(12) =25a(13) =13a(14) =1a(15) =1a(16) =15a(17) =65a(18) =73a(19) =21a(20) =1a(21) =1a(22) =21a(23) =140a(24) =273a(25) =171a(26) =31a(27) =1a(28) =1a(29) =28