Let n>1. If (n^2)+2 is a prime show that 3 divides n.
Can anyone help me start this exercise? Thank you
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Originally Posted by AlexHall Let n>1. If (n^2)+2 is a prime show that 3 divides n. Try proving the contrapositive. If 3 does not divide n then n must be of the form 3k+1 or 3k+2. Show that in both cases (n^2)+2 is then a multiple of 3.
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