Triangle read by rows: T(n,k) = binomial(n+1,k+1)*binomial(2*n-k+1,k)/(n+1), 0<=k<=n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =1a(6) =1a(7) =9a(8) =10a(9) =1a(10) =1a(11) =16a(12) =42a(13) =20a(14) =1a(15) =1a(16) =25a(17) =120a(18) =140a(19) =35a(20) =1a(21) =1a(22) =36a(23) =275a(24) =600a(25) =378a(26) =56a(27) =1a(28) =1a(29) =49