20190628, 03:06  #1 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
11·19·47 Posts 
3,748+ c204 SmallerbutNeeded
Is there any interest in 3,748+ c204 SmallerbutNeeded gnfs cofactor?

20190628, 03:59  #2 
"Curtis"
Feb 2005
Riverside, CA
5279_{10} Posts 
I am personally interested in any majorproject candidate over 200 digits; the closer to 200 the shorter the job and the more iterations we have to learn from, so I'd be happy to run this number as the next forum project if there's sufficient interest. On CADO, it would run I=15 and 34LP, much less taxing RAM requirement (say, 3GB per client rather than 9+).
2330L is on pace to sieve in 90 threadyears, where most threads are hyperthreads; that's about 50 coreyears if we pretend HT does not exist. A C204 should be about 70% that effort, 60 to 65 [hyper]threadyears. Maybe start a new thread to gauge interest? 
20190628, 17:22  #3 
"Carlos Pinho"
Oct 2011
Milton Keynes, UK
2^{2}·1,259 Posts 
I’m in.

20190628, 21:09  #4 
"Dylan"
Mar 2017
250_{16} Posts 
Do we know how much ECM has been done on this cofactor? I would assume at least to the t50 level, since on factordb there is a 51 digit factor of 3^748+1.

20190628, 22:10  #5  
Jun 2012
2·1,753 Posts 
Quote:
How about a full t60 followed by most of a t65? But that’s just a guess. 

20190628, 22:39  #6  
"Dylan"
Mar 2017
250_{16} Posts 
Quote:
6000@43M 2200@110M 39800@260M 24400@850M So I would posit a full t60 + half a t65 (~40k curves). (*) I actually assumed 9000 curves were done at t50 level (B1 = 43M) 

20190628, 23:42  #7 
Nov 2003
1110100100100_{2} Posts 

20190629, 01:15  #8 
Jun 2012
2×1,753 Posts 

20190629, 01:16  #9 
"Dylan"
Mar 2017
2^{4}·37 Posts 

20191109, 01:47  #10 
Jun 2012
2·1,753 Posts 
Ryan Propper was kind enough to ECM 3,748+ to the t65+ level. It is ready for GNFS.
Anyone interested in a poly hunt? The record escore for a C204 is 2.630e15. Suggest focusing on deg 5, as deg 6 is very likely to have inferior performance on a C204. Code:
533439167600904850230361756102700151678687933392166847323827307497363839257031077774321424872955045754669625577486179222154434651598903112919949771321416511589029559325246084363632977829645558547714072241 
20191109, 01:51  #11  
Nov 2003
2^{2}·5·373 Posts 
Quote:


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