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 2014-02-03, 04:49 #1 paulunderwood     Sep 2002 Database er0rr 73418 Posts Why NeRDs_360360? Why did I choose 10^360360-10^k-1? 360360 = 2*2*2*3*3*5*7*11*13 For small primes p, 10^((p-1)*a)==1 (mod p), and so 10^360360-10^k-1 is not divisible by p. Consequently, after sieving, there is about 15% of the range left and we expect to find about 3 primes in the provable range k=90090-360360.
 2014-02-03, 08:19 #2 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 3·52·127 Posts It would have been better to chose a>1290000*log102 for 10^a-10^k-1. With a=360360, the found primes will be swept away in about a year by the TwinGen-ial deluge. a=17#, perhaps?
2014-02-03, 08:33   #3
Thomas11

Feb 2003

77416 Posts

Quote:
 Originally Posted by paulunderwood Consequently, after sieving, there is about 15% of the range left and we expect to find about 3 primes in the provable range k=90090-360360.
What's the total number of candidates left after sieving?

 2014-02-03, 17:08 #4 paulunderwood     Sep 2002 Database er0rr 73418 Posts 42320 candidates were left in the range 90000-360360. Chuck Lasher is crunching 3/19 of this. Thomas, you are crunching 1/19. I crunched some. The rest was put up, ready for others to crunch -- 1 or 2 weeks per file folks.
2014-02-03, 17:10   #5
paulunderwood

Sep 2002
Database er0rr

13·293 Posts

Quote:
 Originally Posted by Batalov It would have been better to chose a>1290000*log102 for 10^a-10^k-1. With a=360360, the found primes will be swept away in about a year by the TwinGen-ial deluge. a=17#, perhaps?
These may be "swept away" from the top5000, but they should stay on the near-repdigit table.

I have exponents 388080 and 471240 sieved.

Last fiddled with by paulunderwood on 2014-02-03 at 17:29

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