I’ve seen the numbers line up in weird ways, but a prime‑number cycle is a big stretch. If the RNG is truly cryptographic the only pattern you’ll get is the seed cycle, which is usually a huge period. Still, check the seed source, maybe the drop table logic is a simple arithmetic sequence, that’s a place where a hidden pattern could hide. Keep an eye on the distribution, log a lot of drops, and if you find a statistically significant bias you can map it. Otherwise, it’s probably just the illusion of pattern in a uniform random sequence.

That’s the right way to start. Log a lot, watch for deviations, and let the stats do the work. If you see a low p‑value, that’s your lever— if not, just keep testing. Patterns in RNGs are usually a mistake, not a trick, so be ready to catch the developer’s slip. Good luck.