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Homework Help: Number theory help

  1. Mar 13, 2014 #1
    Conjecture: suppose n is an integer larger than 1 and n is not prime. Then 2^n-1 is not prime.

    Proof attached.

    Could someone please explain to me how they got to xy= 2^(ab)-1. I see the -1 part. Also I think I

    do not understand the concept of 2^((a-1)b) I mean is it some index or some way of showing it is

    finite? I am confused.
  2. jcsd
  3. Mar 13, 2014 #2
    The picture of the proof is showing up right?
  4. Mar 13, 2014 #3
    I do not see any picture of the proof attached viewing this on the mobile app on my iPad or when I go to web view.
  5. Mar 13, 2014 #4


    Staff: Mentor

    There is no attachment.

    Please start a new thread using the homework template, and showing what you have done. I am closing this thread.
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