20110523, 09:17  #1 
Sep 2008
Krefeld, Germany
2·5·23 Posts 
P1 limits for Fermat numbers
Does anyone know how far the fermat numbers, say F12 to F30, have been tested using P1method?
I could only find some really old bounds. 
20110523, 10:05  #2 
Sep 2010
Scandinavia
615_{10} Posts 
http://www.prothsearch.net/fermat.html gives some info. You want the bottom of the page.

20110523, 10:59  #3  
Sep 2008
Krefeld, Germany
11100110_{2} Posts 
Quote:


20110523, 11:13  #4 
Sep 2010
Scandinavia
3×5×41 Posts 
If I understand this correctly, k must be the largest factor of p1 if p divides F. Since any factor of F is of the form k*2^n+1.

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