I seem to be confused with the proof that if there are only n prime numbers then M=p1*...*pn + 1 is prime. Just because M isn't divisible by prime numbers doesn't mean that it is prime. It also has to not be divisible by any non-prime numbers as well. This rule doesn't work for the primes p1=1, p2=3, p3=5 where M=16 which is obviously not prime.
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I seem to be confused with the proof that if there are only n prime numbers then M=p1*...*pn + 1 is prime. Just because M isn't divisible by prime numbers doesn't mean that it is prime. It also has to not be divisible by any non-prime numbers as well. This rule doesn't work for the primes p1=1, p2=3, p3=5 where M=16 which is obviously not prime.