Number of primitive coronoid systems with n hexagons.

Terms

a(0) =1a(1) =1a(2) =3a(3) =2a(4) =11a(5) =12a(6) =40a(7) =68a(8) =192a(9) =395a(10) =1061a(11) =2432a(12) =6318a(13) =15417a(14) =39660a(15) =99550a(16) =256388a(17) =654003a(18) =1689973a(19) =4355457a(20) =11305165a(21) =29347706a(22) =76527893