Find all primes , given that
Give your answer as the sum of these primes
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Let p = 1 1 , which seems to satisfy the condition, else p is disordered with p + 1 1 . In the second case, p + 1 1 ∣ p ( p + 1 ) ( p + 2 ) if it also divides the product ( p + 1 ) ( p + 2 ) . Which = ( − 1 0 ) ( − 9 ) in m o d p + 1 1 , so it must be true that p + 1 1 ∣ 9 0 , so p ∈ 7 , 1 9 , 7 9
Therefore 7 + 1 1 + 1 9 + 7 9 = 1 1 6