CompleteKaryTree

CompleteKaryTree[n] gives the complete binary tree with n levels.

CompleteKaryTree[n, k] gives the complete k-ary tree with n levels.

Examples

Create a binary tree with 4 levels:

CompleteKaryTree[4]
(* Graph[...] *)

Create a ternary tree with 3 levels:

CompleteKaryTree[3, 3]
(* Graph[...] *)

Please visit the official Wolfram Language Reference for more details.