Bower of Hanoi A pile of $n$ rings, each smaller than the one below it, is on a peg on a board. Two other pegs are attached to the board. In the game called the Tower of Hanoi puzzle, all the rings must be moved, one at a time,to a different peg with no ring ever placed on top of a smaller ring. Find the least number of moves that would be required. Prove your result by mathematical induction.
(THE FIGURE CANNOT COPY)