Number of labeled planar binary trees with 2n-1 elements (external nodes or internal nodes).

A052510

Number of labeled planar binary trees with 2n-1 elements (external nodes or internal nodes).

Terms

    a(0) =1a(1) =6a(2) =240a(3) =25200a(4) =5080320a(5) =1676505600a(6) =821966745600

External references