A square piece of paper is folded in half along a line of symetry. The resulting shape is then folded in half along line of symetry of the new shape. This process is repeted until n folds have been made, given a sequence of n+1 shapes. If we do not distinguish between congruent shapes, find the number of possible sequences when (a) n=3
(b) n=6
(c) n=9