Number of unlabeled 2,3 cacti (triangular cacti with bridges) with n triangles and every node contained in exactly one triangle.

A380634

Number of unlabeled 2,3 cacti (triangular cacti with bridges) with n triangles and every node contained in exactly one triangle.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =2a(4) =6a(5) =18a(6) =66a(7) =265a(8) =1140a(9) =5186a(10) =24588a(11) =120062a(12) =600884a(13) =3066490a(14) =15907266a(15) =83665520a(16) =445317808a(17) =2394928214a(18) =12997988041a(19) =71116953074a(20) =391931826699

External references