Generalized Catalan triangle of Riordan type, called C(1,3).

Terms

a(0) =1a(1) =1a(2) =1a(3) =4a(4) =4a(5) =1a(6) =25a(7) =25a(8) =7a(9) =1a(10) =190a(11) =190a(12) =55a(13) =10a(14) =1a(15) =1606a(16) =1606a(17) =472a(18) =94a(19) =13a(20) =1a(21) =14506a(22) =14506a(23) =4300a(24) =898a(25) =142a(26) =16a(27) =1a(28) =137089a(29) =137089