Number of Dyck paths of knight moves.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =3a(5) =4a(6) =12a(7) =22a(8) =61a(9) =128a(10) =335a(11) =756a(12) =1936a(13) =4580a(14) =11652a(15) =28402a(16) =72209a(17) =179460a(18) =457274a(19) =1151725a(20) =2945129a(21) =7489680a(22) =19228598a(23) =49256157a(24) =126958030a(25) =327072560a(26) =846173899a(27) =2190012371a(28) =5685200054a(29) =14770728584