Triangle read by rows: T(n,k) = number of ways to insert n pairs of parentheses in k words.

Terms

a(0) =1a(1) =2a(2) =1a(3) =5a(4) =2a(5) =1a(6) =14a(7) =8a(8) =2a(9) =1a(10) =42a(11) =24a(12) =8a(13) =2a(14) =1a(15) =132a(16) =85a(17) =28a(18) =8a(19) =2a(20) =1a(21) =429a(22) =286a(23) =100a(24) =28a(25) =8a(26) =2a(27) =1a(28) =1430a(29) =1008