How should i start off this proof?
If (2^n -1) is prime, prove that n is prime.
So far I've only got 2 things written down:
1. If 2^n -1 is prime then using divisor notation. 1|(2^n -1) and (2^n -1)|(2^n -1). But I dont think this helps.
2. To prove this we can prove gcd((2^n -1),n) = 1 (i.e relatively prime)
Other than that not much idea at all.
Any suggestions would be greatly appreciated.