See: <a href="http://io9.gizmodo.com/the-night-the-gamblers-fallacy-lost-people-millions-1496890660" rel="nofollow">http://io9.gizmodo.com/the-night-the-gamblers-fallacy-lost-people-millions-1496890660</a> Dice, decaying atoms and ping pong balls do not have a memory. A D20 has a 5% chance to roll any number every time it is rolled. When i went to college in the dark ages we had to use random number tables, whole books of them were published. They had repetitions, runs of numbers etc. as long as there was no pattern they were true random numbers. The afoementioned page shows the results from hundreds of thousands of rolls, there is no pattern. I am sure you could roll numbers until your mouse wore out and there would be no pattern. The other night one of my players rolled, consecutively 51, 52, 53, he freaked out. I told him if he could roll a 54 I would give him $100. He rolled a 78. People notice what seem to be oddities. You walk to the corner store twice a day for five years, you remember the one time you saw bluebird, you don't remember the 500 times you saw a pigeon.