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Old 2020-09-08, 16:59   #373
bur
 
Aug 2020

25 Posts
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So the number of primes per n decreases stronger than the number of candidates per n?


Here are the n values that produce Riesel primes:

Code:
1281979 * 2^n - 1
0 <= n <= 20000

3
7
43
79
107
157
269
307
373
397
1005
1013
1765
1987
2269
6623
7083
7365
10199
16219


bold values indicate primes
I have completed the same for Proth side, but since it's a work in progress, I'll post once I'm at larger n.
Quote:
You could choose a lower k-value which produce smaller test timings for same n-values as 1281979.
There's a longer story behind why I chose that k... :D

I have two computers at work I can use for crunching, both are using CPU for Primegrid projects. I want to keep it that way, because I like the conjecture solving. So the cheapest way to do more crunching would be to buy to mid-low-end GPUs such as the GTX 1650 and use those for other projects. Then I found out LLR on GPUs is considered a waste of time.

But - there's a new software Proth2.0 that apparently tests Proth primes quite efficiently on GPUs. So I decided to find Proth primes. But PG has three Proth prime subprojects and covers a lot of small k's... Around that time I discovered my birth date is a prime number and also large enough not to interfere with PG. Also that it's prime could result in the interesting combination of prime k, prime n and prime b. I know large k hardly change anything in regard to total digits but make computation slower and I also knew the Nash weight is not that high using nash.exe, but I will keep that k. If I find a mega prime with it it will at least be a somewhat rare k ... ;)

Last fiddled with by bur on 2020-09-08 at 17:09
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