Well technically yeah he could not be rng but it is possible. Yeah the math is a little off cause you are going off the odds of it happening for a total of 4 weeks. The system just sees the current week. So it will just be a simple 1/6 chance to get it each week. Just so happens that since it is completely and utterly random that it did the same one 4 weeks in a row. That is the point of having a random number generator. 1-6 isn't that big of a area of numbers to possibly generate. I'd understand if it was 1-100 or so.