The number of nodes in a full binary tree of depth 4 is
The number of nodes in a full binary tree of depth 4 is 15.
The maximum possible number of null links in a complete binary tree of n nodes is (n+1), where only 1 node exists in bottom-most level to the far left.
A full binary tree is a tree in which every node other than the leaves has two children. A complete binary tree is a binary tree in which every level, except possibly the last, is completely filled, and all nodes are as far left as possible.