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 2017-07-04, 15:09 #199 ATH Einyen     Dec 2003 Denmark 3·17·59 Posts Remaining 5,376 pi prime candidates 750K-1M digits sieved to 245G plus a tiny bit higher non-consecutive ranges: picandidates750K-1M.txt
 2018-03-30, 19:56 #200 davar55     May 2004 New York City 23·232 Posts Any progress on this curious number a(20)? What's the likelihood that a 750k-1M digit candidate will be a PRP? Or that all of the candidates in that range will be composite?
2018-03-31, 01:02   #201
J F

Sep 2013

23×7 Posts

Quote:
 Originally Posted by davar55 Any progress on this curious number a(20)? What's the likelihood that a 750k-1M digit candidate will be a PRP? Or that all of the candidates in that range will be composite?
#20 at 833K digits atm, no PRP.
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%.

 2018-08-09, 13:24 #202 davar55     May 2004 New York City 23·232 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?
2018-08-31, 20:44   #203
davar55

May 2004
New York City

23·232 Posts

Quote:
 Originally Posted by J F #20 at 833K digits atm, no PRP. 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%.

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.

 2019-03-14, 12:46 #204 paulunderwood     Sep 2002 Database er0rr 3·11·107 Posts You can now go up to 31.4 trillion digits Last fiddled with by paulunderwood on 2019-03-14 at 12:47
 2019-03-14, 19:03 #205 petrw1 1976 Toyota Corona years forever!     "Wayne" Nov 2006 Saskatchewan, Canada 23×34×7 Posts Wife of Pi ... Attached Thumbnails
 2019-03-14, 19:05 #206 petrw1 1976 Toyota Corona years forever!     "Wayne" Nov 2006 Saskatchewan, Canada 23·34·7 Posts Pi In trouble. ... Attached Thumbnails
2019-03-19, 13:12   #207
davar55

May 2004
New York City

23×232 Posts

Quote:
 Originally Posted by paulunderwood You can now go up to 31.4 trillion digits
Wow. If a(20) grew that large, for the sake of argument, what resources would be
needed to prove a 31.4 trillion digit number prime (or probably prime)?

2019-03-19, 13:38   #208
paulunderwood

Sep 2002
Database er0rr

1101110010112 Posts

Quote:
 Originally Posted by davar55 Wow. If a(20) grew that large, for the sake of argument, what resources would be needed to prove a 31.4 trillion digit number prime (or probably prime)?
Deep Thought running Primo? Probably to the end of time!

2019-03-19, 14:15   #209
davar55

May 2004
New York City

23·232 Posts

Quote:
 Originally Posted by paulunderwood Deep Thought running Primo? Probably to the end of time!
I don't doubt Deep Thought's abilities, but Hal could probably do it in half that time.

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