Number of length n left factors of Dyck paths having no UUDD's; here U=(1,1) and D=(1,-1).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =8a(6) =14a(7) =23a(8) =41a(9) =69a(10) =124a(11) =212a(12) =383a(13) =662a(14) =1200a(15) =2091a(16) =3799a(17) =6661a(18) =12122a(19) =21359a(20) =38919a(21) =68850a(22) =125578a(23) =222892a(24) =406865a(25) =724175a(26) =1322772a(27) =2360010a(28) =4313155a(29) =7711148