Number of species of genus 1 Latin bi-trades of size n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =1a(9) =0a(10) =1a(11) =10a(12) =21a(13) =123a(14) =565a(15) =3003a(16) =14944a(17) =75985a(18) =371549