Prime95 finding any prime?
Hello Prime95 can you help me I want to find any prime number?
What can I do if I want to find eg, 23 is a prime number ? 
To determine 23 is prime, try dividing by every prime below the square root of 23.
2 and 3 do not divide 23, so 23 is prime. 
[QUOTE=Tamay82;496200]Hello Prime95 can you help me I want to find any prime number?
What can I do if I want to find eg, 23 is a prime number ?[/QUOTE] 2^23==2 mod 23, thus 23 is prime. 
[QUOTE=sweety439;496231]2^23==2 mod 23, thus 23 is prime.[/QUOTE]
2^341==2 mod 341, thus 341 is prime 
[QUOTE=LaurV;496245]2^341==2 mod 341, thus 341 is prime[/QUOTE]
Ha! (19:57) gp > (3411)!%341 %54 = 0 Andrew When in doubt, use Wilson's Theorem :lol: [url]http://fredrikj.net/blog/2012/03/factorialsmodnandwilsonstheorem/[/url] 
[QUOTE=AndrewWalker;496292]Ha! [/QUOTE]
:tu: haha, you made my day! You have however a mistake in the post: you must not say "Ha!", but ":davar55:" (and don't tell me you made 54 trials to get that right! :razz: :shock:) 
I'm not sure how to respond, but anyway! :smile::davar55::shock: I used a few trials, but not that many!
It was interesting exploring how far I could push this test, I got over 1000 but then needed to increase the stack limit in gp so gave up! Main point of my post was the link I shared. Frederik Johansson is the main aurthor of MPMath, Arb, and has made contributions to a number of other mathematical software projects. He made optimisations which let him test Wilson's Theorem up to 15 digits, that's crazy!! Andrew 
I'm not sure I this answers your question, but Prime95 can only test numbers of the form 2[SUP]p[/SUP]  1 for primality.

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