Number of conjugacy classes of subgroups of index n in free group of rank 2.
A057005
Number of conjugacy classes of subgroups of index n in free group of rank 2.
Terms
- a(0) =1a(1) =3a(2) =7a(3) =26a(4) =97a(5) =624a(6) =4163a(7) =34470a(8) =314493a(9) =3202839a(10) =35704007a(11) =433460014a(12) =5687955737a(13) =80257406982
External references
- oeis: A057005