Question 624694
Solution:

P+1 = N^2

P = N^2-1

P = (N-1)(N+1)

But P is prime then N-1=1 or N+1 = 1

N-1 = 1 then N=2 and P = 3
N+1 = 1 then N =0 and P = -1 (not prime)

Answer:  P = 3

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