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Old 2020-11-05, 05:52   #2
Batalov
 
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"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

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Quote:
Originally Posted by bbb120 View Post
1527888802614951*2^120 + 1
1527888802614951 has 16 digits ,
if we calculate and try 10^5 per second ,
it will cost 10^15/(365*24*60*60)/10^5=317.1years for us to find this factor ,
That's irrelevant. (If all you have is a hammer, everything looks like a nail.)

Peter Strasser searched really hard with software shown here and found this factor of F118, and that's the end of this story.

It says it right there - he found it with mmff. That means - using a GPU.

Now, how did I find this one?
Quote:
June 26th, 2014
mmff discovers a new Fermat prime!

48595346636925 * 2^197+1 is a Factor of F195!!!
Serge Batalov found his fifth Fermat factor using a version of mmff extended by himself, for this discovery.
Congratulations to Serge from FermatSearch, for the third factor of the year!
...not just by running mmff. First, I was studying mmff's source for a week and then modified and experimented with it for a few weeks and when I was content with the new extended range (n in range high hundred-ish to low-200-ish) passing all tests, I ran it for several more months (and I paid a bunch for ~20 GPUs on AWS for several months) -- but I did get it. It was not easy, I will tell you that.
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