Number of Dyck paths of knight moves.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =4a(5) =4a(6) =18a(7) =26a(8) =86a(9) =158a(10) =462a(11) =976a(12) =2665a(13) =6082a(14) =16040a(15) =38338a(16) =99536a(17) =244880a(18) =631923a(19) =1583796a(20) =4081939a(21) =10358670a(22) =26728731a(23) =68425494a(24) =176964795a(25) =455967376a(26) =1182454137a(27) =3061954102a(28) =7962768190a(29) =20702327552