The summer school where this was conjectured was http://www.wolframscience.com/summerschool/2003/participants/ http://www.wolframscience.com/summerschool/2003/p

The summer school where this was conjectured was http://www.wolframscience.com/summerschool/2003/participants/ http://www.wolframscience.com/summerschool/2003/participants... As one of the "live experiments" Stephen Wolfram decided to try to find the minimal recursive functions involving arithmetic type operations that produce complex behavior. The article glosses over this, but no one set out to find a function that produced only primes; it just so happened that when enumerating these minimal functions this one was discovered to have a peculiar regularity. By the way, if you ever discover an efficient way to generate primes, you have a shot at claiming a 100k prize (http://www.eff.org/awards/coop http://www.eff.org/awards/coop)