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quickest way to prove primality

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Mar 23.2007

Hi guys:

Trying to write a function to prove is a number is a prime.
Whilst i have it working i don’t think its the most efficient way.

I basically find all the factors of the number and then count how many factors it has, if its 2 its prime. problem there is if i input 123456789, it has to loop through every number between 0 and 123456789.

Any better suggestions?

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4 Comments(s) ↴

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@bathurst_guyMar 23.2007 — when it reaches three break the loop.
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@Sid3335authorMar 23.2007 — yep already does that, i was just wondering if there is a better mathematical way of doing it.
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@bathurst_guyMar 23.2007 — better mathematical way - yes . easy - i dont think so.

See if this [url=http://en.wikipedia.org/wiki/Prime_numbers]wikipedia article[/url] helps.
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