> To me it seem like he either applied an erroneous method or, more likely in my opinion, just had erroneous naive checking Of course the method was erroneous,

> To me it seem like he either applied an erroneous method or, more likely in my opinion, just had erroneous naive checking Of course the method was erroneous, that's not the point I am (apparently rather poorly) trying to get across. My point is that the method seems to have been lost to time, and that it is a shame because while faulty for finding primes it may prove fruitful elsewhere, or may simply be interesting. And if he had a method of checking for primes in the 17th century, this would also be noteworthy and interesting, though it would beg the question of why he stopped presumably before reaching a thousand. My base observation is relatively straightforward and I honestly don't understand the dismissiveness it is met with: Sometime in the early 1600s, Mersenne found M(127). The 'how' is interesting to me because I don't see it likely that this was discovered by random luck, but predicated on a novel method he had developed which, while clearly very flawed, would nonetheless still curious to see. Our math and science textbooks are filled with various flawed methods, why then is this one of seeming no concern?