This appears to be a Linear congruential generator for which the multiplier parameter a = 1. I'm far and far from being a PRNG expert (I'd bet BrowserUk could write a lengthy article on this topic before his first mug of caffeine-delivery-beverage-of-choice in the morning), but I think you need to exercise some caution in chosing the m a c parameters so that the period of the generator is maximized (i.e., equal to m) and the generator never gets "stuck" at a particular value of Xn. See the linked article. Just glancing at this article, I don't see any case in the "Parameters in common use" table of a = 1, so this may be a red flag.

Update: After more thought (and looking at pryrt's post), a multiplier a = 1 does seem to meet all the requirements for maximum period length for this type of PRNG, but gives a boring "clock" progression to the output, i.e., the output always advances by the offset mod S. Don't you want the output to bounce around a bit more and at least seem more random? ;)

Give a man a fish:  <%-{-{-{-<

In reply to Re^2: Check randomly generated numbers have not been used before by AnomalousMonk
in thread Check randomly generated numbers have not been used before by R3search3R

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