单点时限: 2.0 sec
内存限制: 256 MB
A double tower of hanoi contains 2n disks of n different sizes,two of each size.As usual,we’re required to move only one disk at a time,without putting a larger one over a smaller one.
How many moves does it take to transfer a double tower from one peg to another,if disks of equal size are indistinguishable from each other?
There are so many tests.Each test have one interger n(1<=n<=60) represented the number of disks.
Output a single number of the minimum steps in a line.