Triangle read by rows: T(n,k) is the number of length n left factors of Dyck paths having k UUDD's, where U=(1,1) and D=(1,-1).

A191793

Triangle read by rows: T(n,k) is the number of length n left factors of Dyck paths having k UUDD's, where U=(1,1) and D=(1,-1).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =1a(6) =8a(7) =2a(8) =14a(9) =6a(10) =23a(11) =12a(12) =41a(13) =28a(14) =1a(15) =69a(16) =54a(17) =3a(18) =124a(19) =116a(20) =12a(21) =212a(22) =220a(23) =30a(24) =383a(25) =453a(26) =87a(27) =1a(28) =662a(29) =852

External references