Number of conjugacy classes of subgroups of index 3 in free group of rank n.
A057009
Number of conjugacy classes of subgroups of index 3 in free group of rank n.
Terms
- a(0) =1a(1) =7a(2) =41a(3) =235a(4) =1361a(5) =7987a(6) =47321a(7) =281995a(8) =1685921a(9) =10096867a(10) =60524201a(11) =362972155a(12) =2177309681a(13) =13062280147a(14) =78368930681a(15) =470199300715
External references
- oeis: A057009