Earlier this year, Numberphile (which is a fantastic youtube channel) created a very accessible video about this topic. http://www.youtube.com/watch?v=wo19Y4tw0

Earlier this year, Numberphile (which is a fantastic youtube channel) created a very accessible video about this topic. http://www.youtube.com/watch?v=wo19Y4tw0l8 http://www.youtube.com/watch?v=wo19Y4tw0l8