Number of 4-level labeled rooted trees with n leaves.

A000307

Number of 4-level labeled rooted trees with n leaves.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =22a(4) =154a(5) =1304a(6) =12915a(7) =146115a(8) =1855570a(9) =26097835a(10) =402215465a(11) =6734414075a(12) =121629173423

External references