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Old 2016-09-29, 20:36   #12
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Quote:
Originally Posted by henryzz View Post
It sounds like it may be more sensible just to start over.
That is what I'm doing. It is a lot of rework. That is why I've asked for help. I have no idea when I'll be finished. I think I can finish all types to n=100000 by the end of the year, but that depends upon how many of my co-workers help. As for above n=100000, that is more difficult to gauge. Type 7 and 23 have been tested much further than other types, so it means a lot more time will be dedicated to sieving and testing. Fortunately I have sieved about half of the types 3 to 25 to appropriate depths, but will complete sieving all others (minus types 7 and 23) before I start testing the ranges. Type 7 will be absolutely terrible, so I've sent an e-mail to Rene Dohmen hoping that he kept residues for type 7.

Last fiddled with by rogue on 2016-10-14 at 22:00
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Old 2016-10-02, 15:20   #13
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I have more bad news. I have tested to over 40,000 on each of the types. Of the 24 I'm testing, 17 are missing primes with a total of 21 of 48 with missing primes when including both + and -.
Make that 18. I just found a prime missed for type 2.

After much consideration, I have come to the conclusion that some users were running old copies of pfgw or maybe even primeform. It is a fact that older versions of pfgw/primeform had bugs that resulted in primes being found composite. I've seen that on the other projects where I have re-processed old ranges (generalized Cullen and Woodall). Any results prior my taking ownership (circle 2009) are likely suspect and most of the oldest work was done prior to that time.

Last fiddled with by rogue on 2016-10-14 at 22:00
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Old 2016-10-14, 12:37   #14
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Type 16 has been tested up to n=210000.

The following PRPs were found:
Code:
102354!16+1
116340!16-1
116682!16+1
116942!16+1
118266!16+1
123066!16-1
126166!16+1
130200!16-1
145852!16+1
152818!16-1
166316!16+1
167328!16-1
195388!16-1
204430!16+1
I will continue on with types 24 and 25.

Last fiddled with by rogue on 2016-10-14 at 22:01
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Old 2016-10-14, 13:09   #15
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Thank you!

Although your results match known results for ranges known to be searched, you did find one unknown prime with 195388!16-1. That was beyond the known search range.

Are you still planning on searching 24 and 25?
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Old 2016-10-14, 13:59   #16
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with k=1 b= N%K; n=N\K; where \ is the floor of division and c, this is based on the fact that a multifactorial(N,K) is \prod_{r=0}^n {N-rK} which when taken mod K are all the same value so form a power under modular arithmetic mod K. so mod K these values form the same as k*b^n+c.

Last fiddled with by science_man_88 on 2016-10-14 at 14:15
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Old 2016-10-14, 15:37   #17
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Quote:
Originally Posted by rogue View Post
Thank you!

Although your results match known results for ranges known to be searched, you did find one unknown prime with 195388!16-1. That was beyond the known search range.

Are you still planning on searching 24 and 25?
Yes indeed. I've got type 24 running now and am currently at n=~188,000. Once that's done (at n=300,000, if I recall correctly), I'll get type 25 finished up.

Last fiddled with by rogue on 2016-10-14 at 22:01
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Old 2016-10-14, 16:25   #18
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Quote:
Originally Posted by science_man_88 View Post
with k=1 b= N%K; n=N\K; where \ is the floor of division and c, this is based on the fact that a multifactorial(N,K) is \prod_{r=0}^n {N-rK} which when taken mod K are all the same value so form a power under modular arithmetic mod K. so mod K these values form the same as k*b^n+c.
Sorry that I'm being dense, but I fail to see how this will make sieving faster. Please walk me through an example sieving from 1000!7+1 thru 2000!7+1.
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Old 2016-10-14, 16:32   #19
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The entire range for !2 is now retested to 100,000. 76190!2-1 is a new prime that was missed by previous searches. I've been waiting to get to a milestone before posting the new search page. If I'm lucky, it will be reached this weekend.
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Old 2016-10-14, 17:29   #20
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Quote:
Originally Posted by rogue View Post
Sorry that I'm being dense, but I fail to see how this will make sieving faster. Please walk me through an example sieving from 1000!7+1 thru 2000!7+1.
I'm probably dense but I figured I'd mention it. also we know for example from this that mod 7 6^142+1 is congruent to 1000!7+1. we can use this and maybe a few other things ( like what the multiple of 7 is between them) to figure out. I guess I was mostly thinking of eliminating c values so I guess I'm just too stupid.
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Old 2016-10-14, 18:27   #21
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Originally Posted by wombatman View Post
I've got Base 24 running now and am currently at n=~188,000. Once that's done (at n=300,000, if I recall correctly), I'll get Base 25 finished up.
What are you guys calling "bases" here? Isn't it a misnomer? It is all over this thread.

I take it that you are referring to what Davis calls "types", i.e. how many numbers are skipped in a product series.
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Old 2016-10-14, 18:57   #22
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Originally Posted by Batalov View Post
What are you guys calling "bases" here? Isn't it a misnomer? It is all over this thread.

I take it that you are referring to what Davis calls "types", i.e. how many numbers are skipped in a product series.
You are correct. I didn't notice his nomenclature and should have used it.

Outside of a few comments, I have make that change so you will see some posts have been edited.

Last fiddled with by rogue on 2016-10-14 at 22:02 Reason: Change "type" to "base" where appropriate
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