Chef at GYM

So the Chef has become health conscious and is now lifting weights at the gym. But its his first time so the trainer gives him a simple job to do. He has been given a weight lifting rod and N heavy weights, each weighing 20, 21, .... , 2n-1. He has to stick each of the "N" weights on the rod, one after another, in such a way that the right side is never heavier than the left side. At each step he