Isotopy classes of ordered Latin bi-trades of size n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =0a(5) =3a(6) =1a(7) =13a(8) =10a(9) =66a(10) =112a(11) =723a(12) =2283a(13) =12616a(14) =62175a(15) =372420a(16) =2269398a(17) =15225551a(18) =107457456