Sorry if I formatted this thread incorrectly as its my first post ^^ 1. The problem statement, all variables and given/known data For every integer n greater than 2, prove that the group U(n^2 - 1) is not cyclic. 2. Relevant equations 3. The attempt at a solution I've done a problem proving that U(2^n) is not cyclic when n >3, but I'm failing to make a parallel. How does one find the order of (n^2 -1)? Is this information even needed to solve this problem?