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

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =2a(6) =5a(7) =10a(8) =10a(9) =5a(10) =14a(11) =35a(12) =45a(13) =35a(14) =14a(15) =42a(16) =126a(17) =196a(18) =196a(19) =126a(20) =42a(21) =132a(22) =462a(23) =840a(24) =1008a(25) =840a(26) =462a(27) =132a(28) =429a(29) =1716