dario-dsa's blog

Prime number, math problem
By dario-dsa, 11 years ago, In English

Hi, I am having problem with solving this task from my math homework. If number p is prime and p^2+8 is also prime. Prove that p^3+4 is also prime number.

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11 years ago, # |
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Suppose that p ≠ 3. Then thus p2 + 8 is not prime and we were wrong in our assumption. Then p = 3 and p3 + 4 = 31 which is obviously prime.

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    11 years ago, # ^ |
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    How to prove that p2 = 1 mod 3?

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      11 years ago, # ^ |
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      11 years ago, # ^ |
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      Fermat's little theorem. If p is prime, then

      This is a special case of Euler's theorem, which is formulated like this for coprime a, m:

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