Array T(n,k) = number of conjugacy classes of subgroups of index k in free group of rank n, read by antidiagonals.

A057004

Array T(n,k) = number of conjugacy classes of subgroups of index k in free group of rank n, read by antidiagonals.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =1a(7) =7a(8) =7a(9) =1a(10) =1a(11) =15a(12) =41a(13) =26a(14) =1a(15) =1a(16) =31a(17) =235a(18) =604a(19) =97a(20) =1a(21) =1a(22) =63a(23) =1361a(24) =14120a(25) =13753a(26) =624a(27) =1a(28) =1a(29) =127

External references