Proof Writing & Problem Solving · Easy problem

In the Tower of Hanoi, moving $n$ disks takes $T(n) = 2T(n-1) + 1$ moves (move $n - 1$ disks aside, move the largest, move the $n - 1$ back on top), with $T(1) = 1$. Induction gives $T(n) = 2^n - 1$. How many moves does it take for $7$ disks?