20171226, 18:42  #1 
Dec 2017
3 Posts 
M5 is prime!
I got this message buried in my work thread status.
What does this mean? When I looked at my recent results, there was no mention of this. 
20171226, 20:46  #2 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
47·197 Posts 
While M5 is certainly prime, this usually happens when the worktodo.txt file was edited externally, or if there was no space left on disk, or similar.
If something from that spectrum happened, the task file may have contained Test=5 (that is that the line was truncated from, say, Test=51329897 or a similar, more decorated string) so the program happily tested "2^51" and recorded the result in the results.txt 
20171226, 21:57  #3 
6809 > 6502
"""""""""""""""""""
Aug 2003
101×103 Posts
29×317 Posts 
It could also mean that 2^{13}1 is prime (that is the fifth Mersenne prime). But not likely in a results file (unless it was used for testing the computer/software.)

20180301, 22:53  #4  
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
12EB_{16} Posts 
Quote:
2^51=31 is indeed prime. But you don't get fame or GIMPS credit for your computer redoing an already known Mersenne prime, even accidentally, long after its original discovery. 

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