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Old 2019-04-07, 10:56   #1
matzetoni
 
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Default Same residue for cofactor with different number of known factors?

Hey, I recently began doing cofactor-PRPs and got suspicious about this exponent:


https://www.mersenne.org/report_expo...2702347&full=1


The residue did not change after a new factor was found and a new PRP test was done. A coincidence?
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Old 2019-04-07, 11:32   #2
GP2
 
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Quote:
Originally Posted by matzetoni View Post
The residue did not change after a new factor was found and a new PRP test was done. A coincidence?
The residue value does not change with type-5 residues (unless the cofactor turns out to be PRP). This is expected behavior.

Last fiddled with by GP2 on 2019-04-07 at 11:33
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Old 2019-04-07, 11:57   #3
matzetoni
 
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Thanks, I didn't know that. It was just I observed that the residue changed for other exponents, so I was wondering.
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Old 2019-04-07, 14:00   #4
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Quote:
Originally Posted by matzetoni View Post
Thanks, I didn't know that. It was just I observed that the residue changed for other exponents, so I was wondering.
Some older residues are type-1 rather than type-5. Those do change when a new factor is found.
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