It's incredibly fascinating how very simple constructs like primes have such complexity to them. It's very easy for a 14 year old to formulate questions relating to primes that noone can answer.
what I find interesting is the amount of computing power that it takes to calculate.<p>Edit: As an after thought, there are recordings of million digit prime numbers: <a href="http://www.primegrid.com/download/SR5-180062.pdf" rel="nofollow">http://www.primegrid.com/download/SR5-180062.pdf</a>
this is a great example of the title change rule making a title worse<p>i think taglines/subtitles/subject sentences should be eligible for titles too