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Old 2020-10-23, 02:32   #8
a1call's Avatar
"Rashid Naimi"
Oct 2015
Remote to Here/There

2·1,009 Posts

To see if 2p+1 divides 2*p-1 is computationally about as expensive as a PRP test. It is deterministic but not much, much faster than a PRP test and then a N-1 test.
I learned about it from SM and here is an old relevant thread:

Last fiddled with by a1call on 2020-10-23 at 02:33
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