Primes are not so Random

All prime numbers, except 2 and 5, have to end in the digits 1, 3, 7, and 9.  If primes were random, then the last digit would be random too. But researchers at Stanford University recently published findings demonstrating that the last digit is not truly random. In fact, the last digit has a probability distribution that is not uniform. 

Source: http://www.dailymail.co.uk/sciencetech/article-3494148/Prime-numbers-aren-t-random-thought-Researchers-pattern-mathematical-breakthrough.html