Number of Dyck paths of knight moves.

Terms

a(0) =0a(1) =0a(2) =1a(3) =0a(4) =2a(5) =2a(6) =7a(7) =10a(8) =29a(9) =52a(10) =142a(11) =294a(12) =772a(13) =1732a(14) =4451a(15) =10482a(16) =26715a(17) =64908a(18) =165194a(19) =409720a(20) =1044629a(21) =2627712a(22) =6721492a(23) =17079076a(24) =43853111a(25) =112273270a(26) =289390434a(27) =745262022a(28) =1928015211a(29) =4988699442