2551955340

Appears in sequences

• Level of the first leaf (in preorder traversal) of a binary tree, summed over all binary trees with n edges. A binary tree is a rooted tree in which each vertex has at most two children and each child of a vertex is designated as its left or right child.at n=16A120989
• a(n) = binomial(2*n-4,n-1)*(n+3)/n.at n=18A271823