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Old 2020-09-08, 05:39   #369
Aug 2020

25 Posts

I was testing k = 1281979 for n<= 100000 and interestingly the first 10 n for which this is prime are prime themselves. After that unfortunately there's n = 1005 which obviously isn't. But the ratio of n being prime vs being composite continues to be very high for the remainder of the range.

Is that a known property of some k and is it known why it happens? Is there a connection to Mersenne?

Nothing like that on the Proth side, but there the n that yield primes seem to come in pairs of two that are close to each other (5-10% difference). Though it might just be the brain's inbuild pattern recognition going overboard. So I'll keep testing. If there's something the next n should be in the 3e5 range. ;)

Last fiddled with by bur on 2020-09-08 at 05:41
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