I don't really understand what you are doing or what the steps you have not written in are, but n^2+1 isn't prime for some positive integers, eg n=3.
Prove or Disprove that for p1p2....pn +1 is prime for every positive integer n, where p1,p2,....pn are the n smallest prime numbers.
What I did to answer this, I used the fact that n^2 + 1 is prime for all postive integers.
Then substituted (p(1n) x p2(n+1))^2 +1.
is this a valid proof for this question? after all the multiplying and factoring is done?