Number of equivalence classes of Dyck paths of semilength n for the string udu.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =22a(6) =54a(7) =134a(8) =335a(9) =843a(10) =2132a(11) =5409a(12) =13761a(13) =35088a(14) =89638a(15) =229361a(16) =587678a(17) =1507586a(18) =3871589a(19) =9952087a(20) =25604573a(21) =65927447a(22) =169875992a(23) =438016016a(24) =1130103976a(25) =2917412699a(26) =7535482753a(27) =19473430909a(28) =50347508572a(29) =130228143004