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-   -   Why NeRDs_360360? (https://www.mersenneforum.org/showthread.php?t=19117)

 paulunderwood 2014-02-03 04:49

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.

 Batalov 2014-02-03 08:19

It would have been better to chose a>1290000*log[SUB]10[/SUB]2 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?

 Thomas11 2014-02-03 08:33

[QUOTE=paulunderwood;365992]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.[/QUOTE]

What's the total number of candidates left after sieving?

 paulunderwood 2014-02-03 17:08

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.

 paulunderwood 2014-02-03 17:10

[QUOTE=Batalov;366000]It would have been better to chose a>1290000*log[SUB]10[/SUB]2 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?[/QUOTE]

These may be "swept away" from the top5000, but they should stay on the near-repdigit table.

I have exponents 388080 and 471240 sieved. :smile:

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