20170704, 15:09  #199 
Einyen
Dec 2003
Denmark
3,253 Posts 
Remaining 5,376 pi prime candidates 750K1M digits sieved to 245G plus a tiny bit higher nonconsecutive ranges:
picandidates750K1M.txt 
20180330, 19:56  #200 
May 2004
New York City
5·7·11^{2} Posts 
Any progress on this curious number a(20)?
What's the likelihood that a 750k1M digit candidate will be a PRP? Or that all of the candidates in that range will be composite? 
20180331, 01:02  #201  
Sep 2013
2^{3}×7 Posts 
Quote:
Quick (and very rough) approximation that a random pick with n decimal digits is prime: 1 : 2.3n Chance to find none between 750K and 1M is around 90%. 

20180809, 13:24  #202 
May 2004
New York City
5×7×11^{2} Posts 
Any news/progress on a(20)? If things continue as they're going, approximately
when will 1M digits be reached? How significant would the next trial value be, if found probably prime? 
20180831, 20:44  #203  
May 2004
New York City
108B_{16} Posts 
Quote:
Thank you. I sometimes forget the niceties. There's no way to know for sure (yet) that there is or isn't a prime located at the position a(20) in pi. If there is, and it's relatively long, these efforts to find it are interesting as will be the result. If there is no prime at that position, proving which would probably be daunting, then we've hit on an unusual numerical singularity. 

20190314, 12:46  #204 
Sep 2002
Database er0rr
3×1,327 Posts 
You can now go up to 31.4 trillion digits
Last fiddled with by paulunderwood on 20190314 at 12:47 
20190314, 19:03  #205 
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
4,987 Posts 
Wife of Pi
...

20190314, 19:05  #206 
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
4,987 Posts 
Pi In trouble.
...

20190319, 13:12  #207  
May 2004
New York City
5·7·11^{2} Posts 
Quote:
needed to prove a 31.4 trillion digit number prime (or probably prime)? 

20190319, 13:38  #208  
Sep 2002
Database er0rr
3×1,327 Posts 
Quote:


20190319, 14:15  #209  
May 2004
New York City
5×7×11^{2} Posts 
Quote:


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