I became obsessed with this problem recently: http://projecteuler.net/problem=436 http://projecteuler.net/problem=436 and couldn't solve it. I found an articl

I became obsessed with this problem recently: http://projecteuler.net/problem=436 http://projecteuler.net/problem=436 and couldn't solve it. I found an article on mathworld that says the number of expected rolls is e so that the sum is over 1. I don't know how to figure out what the value of the roll that gets you over 1 is, it's something like 0.64 from simulation but what does that number mean and why?