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Old 2020-10-22, 08:35   #8
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Dec 2008
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Originally Posted by ONeil View Post
My code is very fast for some numbers its true, yet for 8 digits you might have to edit the range if you want a long time search. I'm going to try it with the existing code on some 8 digit searches to see if there are any with small 9 digit factors. As you can see I think this beats most if all factoring codes out there with some factoring coding techniques on some numbers.
If you are amazed by this, you'd be completely flabbergasted by learning what is actually possible these days.

? p=1741;m=2^p-1;q=2*p+1;while(m%q,q+=2*p);print(q)
 ***   last result computed in 0 ms.
? p=16273;m=2^p-1;q=2*p+1;while(m%q,q+=2*p);print(q)
 ***   last result computed in 0 ms.
? p=67;m=2^p-1;q=2*p+1;while(m%q,q+=2*p);print(q)
 ***   last result computed in 318 ms.
Note that "ms" = millliseconds. if the PC would be bothered to measure the time it took to find the factors of the first two examples, it would probably have been less than 0.0001 seconds.

Edit: Meh, LaurV is faster than me in posting things... and I even messed up the quote tags now...*
Edit2: and Paul too... I should really consider posting my prime gap stuff in MiscMath!
*Edit3: Thanks, LaurV!

Last fiddled with by mart_r on 2020-10-22 at 09:08 Reason: fixed quote
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