Number of Dyck n-paths all of whose ascents have lengths equal to 1 (mod 4).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =7a(7) =22a(8) =57a(9) =128a(10) =268a(11) =573a(12) =1343a(13) =3434a(14) =9038a(15) =23374a(16) =58649a(17) =144400a(18) =355992a(19) =892336a(20) =2280020a(21) =5892301a(22) =15253305a(23) =39347067a(24) =101177783a(25) =260255812a(26) =671941182a(27) =1743500452a(28) =4542147622a(29) =11858732144