A labeled binary tree containing the labels 1 to n with root 1, branches leading to nodes labeled 2 and 3, branches from these leading to 4, 5 and 6, 7, respectively, and so on. The graph corresponding to the complete binary tree on n nodes is implemented in the Wolfram Language as KaryTree[n, 2].

binary tree | complete ternary tree | complete tree | heap

KaryTree