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Math Help - Proofs with prime numbers.

  1. #1
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    Proofs with prime numbers.

    I'm having a few problems with these questions.

    Determine all the twin primes p and q=p+2 for which pq-2 is also prime.

    For n>1, show that every prime divisor of n!+1 is an odd integer that is greater than n
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  2. #2
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    Quote Originally Posted by MichaelG View Post
    I'm having a few problems with these questions.

    Determine all the twin primes p and q=p+2 for which pq-2 is also prime.

    For n>1, show that every prime divisor of n!+1 is an odd integer that is greater than n

    If p,q > 3 then one of them is -1 (mod 3) and the other one is 1 (mod 3) so their product is -1 (mod 3) and thus...

    The question about n!+1 is completely trivial if you dive a little deep into the definitions of these things.

    Tonio
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