334576

Appears in sequences

• Array T(n,k) = number of conjugacy classes of subgroups of index k in free group of rank n, read by antidiagonals.at n=31A057004
• Number of conjugacy classes of subgroups of index n in free group of rank 5.at n=3A057008
• Number of conjugacy classes of subgroups of index 4 in free group of rank n.at n=4A057010
• n*a(n+1) = (2*n^2+3*n+2)*a(n)-(n^2-n-2)*a(n-1); a(0)=1, a(1)=0.at n=7A259901