Prime factors of (2^(mn)-1)/((2^m-1)(2^n-1))

  • Level: Graduate 
  • Thread starter Thread starter helgamauer
  • Start date Start date
  • Tags Tags
    Exponents
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
1 reply · 2K views
helgamauer
Messages
8
Reaction score
0
We have:
z = (2^(mn) - 1)/[(2^m - 1)(2^n - 1)], where (2^m - 1) and (2^n - 1) are prime numbers.
Prove that (2^m - 1) and (2^n - 1) are not the only prime factors of z.

I tried to solve it writing z = (2^m - 1)^a * (2^n - 1)^b and proving that it is not correct. But I don't know how. I also noticed that it would be sufficient to prove that 2^(mn) - 1 can't be written as ((2^m - 1)^x * (2^n - 1)^y but I also have no idea how to prove it. I tried with comparing highest exponents, but nothing..
It will be fantastic if you help me with proving this fact.
 
Physics news on Phys.org


* And i meant (2^m -1) and (2^n -1) are two different ODD primes. May anybody help?