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Old 2020-11-06, 04:45   #19
bbb120
 
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Feb 2019
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Quote:
Originally Posted by Gary View Post
Going back to your original question, the answer depends on what you meant by "get the F118 factor":

- If you just want to re-discover the factor of F118 for fun, you can do that using any of the "Sieve+trial division" programs listed at FermatSearch/Download by giving it a search range of N = 120, K = 1527888802614951. This will take just a fraction of a second to run.

- If you want to find a new factor of F118 that is of similar size as 1527888802614951*2^120+1, that is no longer possible because for N = 120-129 all K values up to 3.2 * 10^15 have already been searched. You can find what has already been searched for any range of N at FermatSearch/STATS/Merge Tables.

- If you want to try to find a new factor of F118 (or ay other Fermat number), go to the FermatSearch Merge Tables and, for your range of N, find the highest K searched so far. Then select a range of K just above that. For example, for N = 120 you could select 3.2 * 10^15 to 3.3 *10^15. Reserve the range via FermatSearch, select an appropriate program via the Download page, and then start your search. And then hope you are very, very lucky
I do not want to find any factor of fermat number ,because it is very difficult to find one ,I only want to know the algorithm behind it
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