Miles Parker wrote:

> And correct me if I'm wrong, but there are some algorithms in which 
> using a prime number would be a bad idea. Anyway, it seems to me that 
> any decent random stream generator should be able to take an arbitrary 
> seed and produce a good result.

Primes etc. are really a figment of early linear congruential 
generators, for which non-prime parameters in the generator itself were 
famously bad choices (actually, not just non-prime but 
non-relatively-prime).  Knuth III is very interesting in that regard.

It's not the case for modern generators.