Number of meanders of length n with Dyck-steps avoiding the consecutive steps UDU and DUD.

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =3a(5) =4a(6) =6a(7) =9a(8) =14a(9) =21a(10) =33a(11) =50a(12) =79a(13) =121a(14) =192a(15) =296a(16) =471a(17) =730a(18) =1164a(19) =1812a(20) =2894a(21) =4521a(22) =7230a(23) =11328a(24) =18135a(25) =28485a(26) =45642a(27) =71844a(28) =115203a(29) =181674