Given that are prime numbers , find the number of all possible values of .
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Note modulo 3 , p + 1 0 ≡ p + 1 , p + 1 4 ≡ p + 2 . Therefore, one of p , p + 1 0 , p + 1 4 is divisible by 3 . Since each number is prime, we conclude one of p , p + 1 0 , p + 1 4 is equal to 3 . Since p is positive, we must have p = 3 .
We easily verify that p = 3 does in fact yield 3 prime numbers (namely 3 , 1 3 , 1 7 ). Therefore, there is one such value of p , so the answer is 1 .