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.