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Old 2020-09-08, 20:02   #375
bur
 
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Quote:
Originally Posted by VBCurtis View Post
Nope. But the opposite isn't true, either.
But then I would say low weight doesn't really matter. Either I test 100000 candidates for a given k and find 10 primes or I test 10000 and find one. Then move to the next low weight k and in the end I end up with the same number of LLRs and primes. Just spread over more than one k. Is it like that?
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Old 2020-09-08, 23:30   #376
VBCurtis
 
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We have no evidence otherwise, though some folks around here do think otherwise.

I test a couple low-weight k's as well as some of the highest; I like finding anomalies, but I don't think my choices are more prime-worthy per unit of search effort.
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Old 2020-09-09, 07:21   #377
bur
 
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I looked into the matter why only primes show up as n for low n values. Here are some restrictions I found:

If n \equiv 0 \textrm{ mod } 2 the Riesel number will be divisible by 3 (n = 2, 4, 6, 8, 10, ...)
If n \equiv 1 \textrm{ mod } 10 the Riesel number will be divisible by 11 (n = 11, 21, 31, 41, 51, ...)
If n \equiv 1 \textrm{ mod } 8 the Riesel number will be divisible by 17 (n = 9, 17, 25, 33, 41, 49, ...)
If n \equiv 15 \textrm{ mod } 20 the Riesel number will be divisible by 41 (n = 15, 35, 55, 75, ...)
If n \equiv 19 \textrm{ mod } 70 the Riesel number will be divisible by 71 (n = 19, 89, 159, 229, ...)

There might be more. I am not sure though if this will rather hit composites than primes. The 2nd condition removes 11, 31, 41, 71, so it doesn't really seem like it.

Last fiddled with by bur on 2020-09-09 at 07:35
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Old 2020-09-09, 09:54   #378
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Haha, I just realized this is probably trivial and occurs for every divisor... yes, I'm not that good at math. :)
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Old 2020-09-09, 20:46   #379
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Here are the n values for Riesel primes with k = 1281979 and n <= 100000


3
7
43
79
107
157
269
307
373
397
1005
1013
1765
1987
2269
6623
7083
7365
10199
16219
26143
32557
38165
47167
47863
70373
94723
95167
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Old 2020-09-19, 13:26   #380
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The (near-)Woodall k's listed in https://www.mersenneforum.org/showpo...&postcount=363, again except for k=1993191, have been completed to n=375k. The only prime found was 667071*2^373497-1.

Edit: Another prime, 667071*2^358286-1, was already reported (by me) to the Prime-Wiki in August, so I accidentally left it off here.

Last fiddled with by Happy5214 on 2020-09-19 at 13:38 Reason: Forgot a prime
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Old 2020-10-01, 11:16   #381
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I've completed the remaining RPS 9th and 10th Drive k's with missing ranges from n=300k to 325k. 18 primes were found, which are attached. It'll probably be until the end of 2021 before they're finished to n=400k, the ultimate goal.
Attached Files
File Type: txt RPS_300-325K.txt (255 Bytes, 7 views)
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