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 2007-12-24, 17:21 #34 Xentar     Sep 2006 Germany 2·5·19 Posts 1 or 2 months ago, I started Sierpinski, Base 18. Think, I will continue this search. k = 122 Sieved till 4P (can anyone tell me, how to calculate the optimal sieve depth?) LLR till n=128000
2007-12-24, 19:30   #35
gd_barnes

May 2007
Kansas; USA

5·2,179 Posts

Quote:
 Originally Posted by Xentar 1 or 2 months ago, I started Sierpinski, Base 18. Think, I will continue this search. k = 122 Sieved till 4P (can anyone tell me, how to calculate the optimal sieve depth?) LLR till n=128000
Hi Xentar; welcome to the effort! I'll show this one as reserved by you.

Quick question...Have you already LLR'd until n=128000 or is that how far you are going to LLR it in the future?

You should sieve until the rate at which candidates are being removed approximately equals the rate at which they can be LLR'd.

To be very specific, you should do an LLR test of ONE candidate that is at 70% of the n-range that you are sieving and sieve until the removal rate equals that testing time. So if you are sieving n=100K-200K, you should run an LLR test on a candidate around n=170K (one that already has small factors removed). However long that takes to LLR is the removal rate you should sieve to. Sieving to P=4P (same as P=4000T if I remember correctly) sounds a bit high but I don't know what range of n you are sieving.

Gary

 2007-12-25, 16:20 #36 Xentar     Sep 2006 Germany 2×5×19 Posts Hi, yes, I have already LLR'd to n = 130000, and I will try to do it, until I find a prime ;) I sieved till n = 1,000,000. At the moment, I get a rate of 20 minutes per factor, and I need about half an hour per LLR test. So I think, I can continue sieving a while. Ok, thank you. Edit: Another question. When I started Sierpinski Base 18, I was told that there are three more k: 18, 324 and 381. For 381 I found a prime - but what is with 18 and 324? There were some "problems", because the k = base, but don't we need to find a prime here, too? Last fiddled with by Xentar on 2007-12-25 at 16:25
2007-12-25, 16:48   #37
gd_barnes

May 2007
Kansas; USA

1089510 Posts

Quote:
 Originally Posted by Xentar Hi, Another question. When I started Sierpinski Base 18, I was told that there are three more k: 18, 324 and 381. For 381 I found a prime - but what is with 18 and 324? There were some "problems", because the k = base, but don't we need to find a prime here, too?
For now, we are not searching k's that are multiples of the base due to some of the issues involved. In this case, k=18 and k=324 for Sierp Base 18 are Generalized fermat #'s and are unlikely to yield a prime with current technology. See the last para. of the project definition in the 'Come join us' thread. The same issue exists for Sierp Base 22 for k=22 and k=484.

We will take up the issue of multiples of the base after the project has been going for a month or two.

Thanks,
Gary

 2007-12-25, 16:59 #38 Xentar     Sep 2006 Germany BE16 Posts Ah ok, thank you. So I will just do k = 122
2007-12-25, 20:39   #39
mdettweiler
A Sunny Moo

Aug 2007
USA (GMT-5)

3·2,083 Posts

Woo hoo! I found a prime! And it's my first prime ever!

I don't think it qualifies for top-5000 status, but here's what I found in my lresults.txt file today as a nice little Christmas present:

4885*2^243388+1 is prime!

This prime is equivalent to 4885*16^60847+1; this means that k=4885 has been eliminated for Sierpinski Base 16!

k=4885 has been searched up to n=60973; it went a little over since I didn't notice the prime until a few more candidates for that k had been tested. I am unreserving k=4885; the remaining sieved candidates (up to n=100,000) are attached to this post in case anyone wants to search this k further.

Also included in the archive attached to this post are the residuals for both k=2908 and k=4885 up to n=60973 (for k=4885) and n=61188 (for k=2908). I am still searching k=2908.
Attached Files
 k4885-sievefile_and_k4885-k2908-residuals.zip (37.6 KB, 338 views)

Last fiddled with by gd_barnes on 2010-05-16 at 07:13

2007-12-26, 03:16   #40
gd_barnes

May 2007
Kansas; USA

5·2,179 Posts

Quote:
 Originally Posted by Anonymous Woo hoo! I found a prime! And it's my first prime ever! I don't think it qualifies for top-5000 status, but here's what I found in my lresults.txt file today as a nice little Christmas present: 4885*2^243388+1 is prime! This prime is equivalent to 4885*16^60847+1; this means that k=4885 has been eliminated for Sierpinski Base 16! k=4885 has been searched up to n=60973; it went a little over since I didn't notice the prime until a few more candidates for that k had been tested. I am unreserving k=4885; the remaining sieved candidates (up to n=100,000) are attached to this post in case anyone wants to search this k further. Also included in the archive attached to this post are the residuals for both k=2908 and k=4885 up to n=60973 (for k=4885) and n=61188 (for k=2908). I am still searching k=2908.
Yeehaw! 55 k's to go on Sierp base 16. I'll remove it from the big sieve.

Gary

2007-12-26, 03:46   #41
gd_barnes

May 2007
Kansas; USA

1089510 Posts

Cut-and-paste from tcadigan's prime find on Sierp base 16. Not moved here because it would be prior to first post.

Quote:
 Originally Posted by tcadigan 7773*2^199784+1 is prime! Time: 213.884 sec. i.e. 7773*16^49946+1 60145 digits I'll try my 6663 to 100K next

 2007-12-26, 17:08 #42 gd_barnes     May 2007 Kansas; USA 5×2,179 Posts Sierp base 12 and Riesel base 13 update Status from Carlos (em99010pepe): 404*12^n+1 is complete to n=79.6K. He decided not to test 288*13^n-1 so that one is now available. It had already been tested to n=62K and a sieved file is available in the sieving thread up to n=100K. Gary
 2007-12-26, 19:51 #43 tnerual     Oct 2006 4038 Posts 32673*2^101924+1 is prime! Time: 51.669 sec. or 32673*16^25481+1
2007-12-26, 20:45   #44
gd_barnes

May 2007
Kansas; USA

5·2,179 Posts

Quote:
 Originally Posted by tnerual 32673*2^101924+1 is prime! Time: 51.669 sec. or 32673*16^25481+1
Great; another down and 54 k's to go for Sierp base 16. That was a quick one; just above our prior testing limit of n=25K.

Are you searching any more k's right now? If so, I'll show them reserved by you to keep any double-work from happening. Also, if you want a file sieved to P=400G on any k that you're interested in for Sierp base 16, I can send it to you ~10-11 PM today CST US (4-5 AM Thurs. GMT) after our big sieve is done to that point.

Thanks for searching.

Gary

Last fiddled with by gd_barnes on 2007-12-26 at 20:50

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