20190323, 15:59  #1 
Apr 2010
Over the rainbow
2·7·173 Posts 
embarking on the long journey
So I'll try in the coming month to try to find a fermat factor, specifically in k*2^347+1 and k*2^348+1.
I'm using gfndsieve for my initial sieve. But i'm wondering if using Srsieve or sr2sieve might be faster after a while. Any one have experience on this? Last fiddled with by firejuggler on 20190323 at 16:28 
20190323, 22:06  #2 
"Mark"
Apr 2003
Between here and the
1724_{16} Posts 
gfndsieve will be many times faster than any of the srsieve programs for this type of number. To put it simply, gfndsieve is a fixed n sieve and srsieve is a fixed k sieve and solving for k when n is known is much easier than solving for n when k is known.

20190323, 23:13  #3 
Apr 2010
Over the rainbow
2×7×173 Posts 
Ok, thank you rogue. I'll try to post update when and IF i get a result.

20190407, 00:06  #4 
Apr 2010
Over the rainbow
2×7×173 Posts 
ok, progress update : ~470 Million number tested, 800850 test/sec, no GF/GFN .
100e9111e9 range tested with 2^347 and 2^348. Last fiddled with by firejuggler on 20190407 at 00:06 
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