Triangle of numbers of semi-meanders of order n with k components.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =1a(7) =3a(8) =6a(9) =4a(10) =1a(11) =4a(12) =11a(13) =16a(14) =10a(15) =1a(16) =5a(17) =17a(18) =37a(19) =48a(20) =24a(21) =1a(22) =6a(23) =24a(24) =66a(25) =126a(26) =140a(27) =66a(28) =1a(29) =7