A number triangle based on the Catalan numbers.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =1a(6) =5a(7) =5a(8) =3a(9) =1a(10) =14a(11) =14a(12) =10a(13) =4a(14) =1a(15) =42a(16) =42a(17) =35a(18) =17a(19) =5a(20) =1a(21) =132a(22) =132a(23) =126a(24) =74a(25) =26a(26) =6a(27) =1a(28) =429a(29) =429