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Old 2020-10-21, 16:32   #43
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storm5510's Avatar
Aug 2009

1,811 Posts

Originally Posted by LaurV View Post
For fun, I just timed factor5 (the old version from 2009, I don't have newer) and it is about few thousand times faster compared with the script (slow laptop, 6 threads in 2 cores to feed the cpu 100%, P95 running in background, i.e. doing nothing due to priority limit, computer still normally responsive).
I believe M1277 has been factored to 2^67. I have both the old and the new factor5 here somewhere. The new doesn't know from 2^? It uses k only. Somewhere in my notebook I keep, there is a conversion formula I scratched down a long time ago. Someone here presented the formula. Who or when, I cannot remember.

After doing a little searching in my notes, I believe I found it. It looks like so: k = 2x / 2p. The x would be replaced with 67 then 68. 2p is 2*1277. If this is correct, the lower k would be 57,781,500,622,426,160, and the upper is 115,563,001,244,852,320. I do not believe it multi-threads, so it could take decades, if not centuries, to run.

I found the archive. It is attached below if anyone wants to mess with it. It produces a results file, but no interim screen output. Luigi Morelli wrote this in 2018. I believe many here know who Luigi is.
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