Primes of the form n^2 - 1?

[Jud McCranie]

At 04:57 PM 5/24/2005, Alonso Del Arte wrote:
>There are plenty of primes of the form n^2 + 1 (even if it's not known
>whether they're infinite) but are there any primes of the form n^2 - 1
>besides 3?
>
>Is there some well-known theorem or conjecture on the subject I have 
>overlooked?

I conjecture that n^2-1 factors into (n-1)(n+1) and none of them are prime, 
except when n=2.