Number of canonical polygons of n sides.

Terms

a(0) =0a(1) =0a(2) =1a(3) =3a(4) =3a(5) =9a(6) =13a(7) =52a(8) =140a(9) =501a(10) =1763a(11) =6785a(12) =25571a(13) =99907a(14) =392230a(15) =1564989a(16) =6297892a(17) =25601641a(18) =104846143a(19) =432629580