Forum: Riesel Prime Search
2021-03-01, 09:52
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Replies: 401
Views: 59,956
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Forum: Miscellaneous Math
2021-02-26, 08:55
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Replies: 11
Views: 372
Thanks for the links, sweety439. To be honest,...
Thanks for the links, sweety439. To be honest, understanding that Boklan and Conway paper is beyond me. So the conjecture says the number of primes is not only finite, but that there are only a few,...
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Forum: mersenne.ca
2021-02-26, 07:01
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Replies: 7
Views: 237
Ok, thanks.
I didn't mean that all prime...
Ok, thanks.
I didn't mean that all prime factors have to be shown in their full decimal representation regardless of size. Have a look at the site now (manual reload might be required), that's...
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Forum: mersenne.ca
2021-02-25, 08:44
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Replies: 7
Views: 237
I think I now understand that the layout comes...
I think I now understand that the layout comes from factorizing the number and every time a factor is found it's added, until only one is left and that isn't show because work is done.
But why not...
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Forum: mersenne.ca
2021-02-25, 08:06
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Replies: 7
Views: 237
List of factors on mersenne.ca
Take for example 2^1051-1 (https://www.mersenne.ca/exponent/1051). It's listed as fully factored, yet the website only shows 3 of these factors and says "Known prime factors (3 factors, 456.3 bits,...
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Forum: Miscellaneous Math
2021-02-24, 18:38
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Replies: 11
Views: 372
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Forum: Miscellaneous Math
2021-02-24, 14:07
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Replies: 11
Views: 372
Mersenne-Woodall Primes
I saw that 2^{521} - 1 is a Mersenne prime and also the Woodall prime 512 * 2^{512} - 1.
A Mersenne number is a Woodall number if the exponent p is of the form 2^n + n. So obviously we need p to...
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Forum: Proth Prime Search
2021-02-18, 06:57
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Replies: 8
Views: 440
I think the breaking-off-or-not depends on the...
I think the breaking-off-or-not depends on the time-scale. Splitting the range will speed up the sieving at the moment. However, in the long run overall sieving time would be shorter when sieving...
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Forum: Homework Help
2021-02-16, 10:23
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Replies: 8
Views: 469
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Forum: Homework Help
2021-02-16, 09:03
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Replies: 8
Views: 469
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Forum: Homework Help
2021-02-16, 08:54
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Replies: 8
Views: 469
Number of primes 2^n-1 within certain range of n
I wanted to calculate how many primes of the form 2^n - 1 can be exptected within a certain range of n based purely on the prime number theorem x/ln(x), no special considerations such as n has to be...
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Forum: Information & Answers
2021-02-14, 06:54
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Replies: 11
Views: 847
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Forum: Proth Prime Search
2021-02-13, 07:33
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Replies: 8
Views: 440
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Forum: Proth Prime Search
2021-02-12, 06:54
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Replies: 8
Views: 440
LaurV, thanks for the advice.
I read here...
LaurV, thanks for the advice.
I read here and at PG that time per factor found increases only with sqrt(n), so I was explicitly told not to split the sieve. At the beginning I did just that...
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Forum: Proth Prime Search
2021-02-11, 18:41
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Replies: 8
Views: 440
Proth primes with k = 1281979
Because I was interested how sieving worked and also wanted to test Proth20 (proth testing for GPU), I started looking at 1281979 * 2^n +1.
That k is large enough not to get into PG's various...
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Forum: Riesel Prime Search
2021-01-26, 07:13
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Replies: 238
Views: 38,173
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Forum: And now for something completely different
2021-01-21, 07:36
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Replies: 3
Views: 546
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Forum: And now for something completely different
2021-01-20, 12:51
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Replies: 3
Views: 546
Correction: Should read "high weight".
And...
Correction: Should read "high weight".
And now that I thought about it some more, k = 1153#-1 is a large k with few small factors but more elegant than using a 486 digit prime. Maybe that's the...
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Forum: And now for something completely different
2021-01-20, 09:43
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Replies: 3
Views: 546
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Forum: Data
2021-01-12, 11:40
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Replies: 5
Views: 5,165
From the Primo FAQ...
From the Primo FAQ (http://www.ellipsa.eu/public/primo/primo.html#FAQ):
For serious prime search you might as well setup a Linux machine, but for just playing around it would be nice to have a...
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Forum: Riesel Prime Search
2020-12-16, 09:08
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Replies: 88
Views: 22,202
I find it really inspiring how long you've been...
I find it really inspiring how long you've been working on this k. I started sieving for Proth k=1281979 some months back, now I'm at around 250T as well, but only for n < 4.1M. So 2 cores produce a...
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Forum: Riesel Prime Search
2020-12-14, 07:05
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Replies: 238
Views: 38,173
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Forum: And now for something completely different
2020-11-11, 18:18
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Replies: 14
Views: 1,373
Two questions... ;)
Firstly: why choose...
Two questions... ;)
Firstly: why choose the form x + y * z# +1? It's specifically the x + ... I don't get. If you want to go for N-1, wouldn't that require a product + 1? So why not test x * z#...
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Forum: And now for something completely different
2020-11-10, 18:15
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Replies: 40
Views: 14,819
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Forum: Proth Prime Search
2020-10-18, 15:42
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Replies: 27
Views: 12,019
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