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2012-01-10, 17:36   #67
rogue

"Mark"
Apr 2003
Between here and the

5×1,307 Posts

Quote:
 Originally Posted by Batalov After sieving, the remaining n's for these are 1 (mod 3), so they don't benefit from algebraic factorization. Shouldn't be 0.
Thanks. Clearly a bug in my code. I need to investigate.

 2012-01-10, 17:57 #68 rogue     "Mark" Apr 2003 Between here and the 11001100001112 Posts Here is a better list (bug fixed) with differences listed: Code:  8*86^n+1 1017 848 32*87^n+1 342 342 8*182^n+1 389 269 27*252^n+1 2164 1855 8*263^n+1 363 298 27*328^n+1 870 758 8*353^n+1 613 613 8*426^n+1 1288 802 8*428^n+1 655 397 8*497^n+1 943 738 8*758^n+1 549 501 8*785^n+1 588 410 8*828^n+1 1136 529 8*930^n+1 1645 1144 8*953^n+1 1155 795 4*72^n-1 1211 838 8*321^n-1 1017 817 8*328^n-1 915 774 9*636^n-1 2840 1758 8*665^n-1 1582 972 9*688^n-1 1252 641 32*702^n-1 2339 2216 8*761^n-1 1527 2285 8*867^n-1 836 475 8*761^n-1 must have the wrong value in the list as the Geoff's last version of srsieve and my version give the same value.
 2012-01-11, 08:11 #69 gd_barnes     May 2007 Kansas; USA 25·331 Posts We should never have a k remaining on the pages where algebraic factorization would bring the weight to 0. Those should always be shown as eliminated by "partial algebraic factorization". I see that is no longer the case with your corrected code so that is a good thing. Still...please check your code again. You'll need to enlighten me on how any n's are removed due to algebraic factors on 8*761^n-1. On a sieve with srsieve to P=511 for n=100001-110000, there are 2285 n's remaining, none of which are divisible by 3. (Maybe I'm missing something.) That's one of only 3 that I spot checked. Last fiddled with by gd_barnes on 2012-01-11 at 08:15
2012-01-11, 13:55   #70
rogue

"Mark"
Apr 2003
Between here and the

5×1,307 Posts

Quote:
 Originally Posted by gd_barnes We should never have a k remaining on the pages where algebraic factorization would bring the weight to 0. Those should always be shown as eliminated by "partial algebraic factorization". I see that is no longer the case with your corrected code so that is a good thing. Still...please check your code again. You'll need to enlighten me on how any n's are removed due to algebraic factors on 8*761^n-1. On a sieve with srsieve to P=511 for n=100001-110000, there are 2285 n's remaining, none of which are divisible by 3. (Maybe I'm missing something.) That's one of only 3 that I spot checked.
The code is fixed. My last post here has the correct numbers, therefore ignore my erroneous post. My point on R761 was that the first post in this thread had the wrong value (probably a copy&paste error). With srsieve 0.6.17 it should have been 2285, not 1527. With srsieve 1.0.1, it is still 2285. In other words, although some n are removed due to algebraic factorizations, those same n have small factors.

Fortunately I haven't been affected with the bases (but was close). I had sieved a couple of k that I had reserved, but hadn't loaded them into my server yet. I just need to resieve them, costing me about 1 week on a single core per k.

2012-01-12, 08:37   #71
gd_barnes

May 2007
Kansas; USA

25·331 Posts

Quote:
 Originally Posted by rogue The code is fixed. My last post here has the correct numbers, therefore ignore my erroneous post. My point on R761 was that the first post in this thread had the wrong value (probably a copy&paste error). With srsieve 0.6.17 it should have been 2285, not 1527. With srsieve 1.0.1, it is still 2285. In other words, although some n are removed due to algebraic factorizations, those same n have small factors. Fortunately I haven't been affected with the bases (but was close). I had sieved a couple of k that I had reserved, but hadn't loaded them into my server yet. I just need to resieve them, costing me about 1 week on a single core per k.
Ah OK. For some reason, I thought you were implying that the weight should be 1527 for R761. Obviously the first post in this thread erroneously showed that value and that is what you were getting at. It has now been corrected to 2285.

I'm out of town for about 9-10 more days. After inspecting these a little closer after I get back, I'll change the first post to account for the n's removed due to algebraic factors.

2012-01-12, 14:22   #72
henryzz
Just call me Henry

"David"
Sep 2007
Liverpool (GMT/BST)

174316 Posts

Quote:
 Originally Posted by gd_barnes Ah OK. For some reason, I thought you were implying that the weight should be 1527 for R761. Obviously the first post in this thread erroneously showed that value and that is what you were getting at. It has now been corrected to 2285. I'm out of town for about 9-10 more days. After inspecting these a little closer after I get back, I'll change the first post to account for the n's removed due to algebraic factors.
Might be nice to list both. I can imagine people might be interested in searching ks with or without algebraic factors.

2012-01-26, 10:44   #73
gd_barnes

May 2007
Kansas; USA

1059210 Posts

Quote:
 Originally Posted by rogue Here is a better list (bug fixed) with differences listed: Code:  8*86^n+1 1017 848 32*87^n+1 342 342  8*761^n-1 must have the wrong value in the list as the Geoff's last version of srsieve and my version give the same value.
The list looks good. I have updated the 1st posting to remove n's with algebraic factors from the weights. Thanks Mark!

Gary

 2012-02-04, 02:49 #74 rogue     "Mark" Apr 2003 Between here and the 5×1,307 Posts With my latest changes to srsieve, some of these get to change once again. I don't think that any of the Sierpinski ones are affected, but some of the Riesel ones are, notably those where k=16 (2^4 and 4^2) and k=64 (2^6, 4^3, and 8^2). I computed these weights. Would someone care to see if I've made a mistake? 64*177^n-1 1016 64*425^n-1 948 16*333^n-1 1389 64*741^n-1 2016
 2012-02-04, 03:34 #75 gd_barnes     May 2007 Kansas; USA 25×331 Posts These look good but wouldn't the previous version of srsieve have picked up k=16 correctly since it is only a perfect square? (Or perhaps it was just overlooked in the scheme of things in these lists?) I can see why the previous version would have missed picking up some algebraic factors for k=64 since it is both a square and cube. I have changed the first post. Last fiddled with by gd_barnes on 2012-02-04 at 03:34
2012-02-04, 04:59   #76
rogue

"Mark"
Apr 2003
Between here and the

5×1,307 Posts

Quote:
 Originally Posted by gd_barnes These look good but wouldn't the previous version of srsieve have picked up k=16 correctly since it is only a perfect square? (Or perhaps it was just overlooked in the scheme of things in these lists?) I can see why the previous version would have missed picking up some algebraic factors for k=64 since it is both a square and cube.
v1.0.1 only looked for the lowest K such that k=K^x. It never considered whether or not x had factors. I believe that one of those conjectures was reserved, so whomever is working on it should use v1.0.2 to eliminate more n. In other words if their current sieve file has n that srsieve v1.0.2 removes via algebraic factorizations, then they should remove those n from their sieve file.

Last fiddled with by rogue on 2012-02-04 at 05:00

 2012-03-08, 04:31 #77 MyDogBuster     May 2008 Wilmington, DE 54448 Posts Added 24*123^n-1 reserved in the PRPNet2 drive to n=250K Weight is 2758 Last fiddled with by MyDogBuster on 2012-03-08 at 04:55

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