I'm not sure at all how to start in answering the following:
GCD (a^(m) - 1, a^(n) - 1) = a^GCD(m, n) - 1
Are there any other properties of GCD other than GCD (a, b) = GCD (a - b, b)?
djino
"What that even help?"
Does $\displaystyle a^{(m,n)}-1|a^m-1$ and $\displaystyle a^{(m,n)}-1|a^n-1$? Why can't any value greater than $\displaystyle a^(m,n)-1$ divide both of them?