Same as A002880, but with orientation-reversing isomorphisms forbidden.

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =3a(5) =2a(6) =12a(7) =16a(8) =59a(9) =133a(10) =445a(11) =1248a(12) =4162a(13) =13014a(14) =43474a(15) =143304a(16) =484444a(17) =1639388a(18) =5617205a(19) =19332596a(20) =67048051a(21) =233691112a(22) =819121608a(23) =2884443024a(24) =10204104900a(25) =36247138920a(26) =129264732757a(27) =462661038926