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Old 2008-08-06, 17:38   #1
masser
 
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Default Twenty Oldest Primes on Top 5000 List

http://primes.utm.edu/primes/search.php?MinAge=2860
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Old 2008-08-07, 01:44   #2
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M32, M33, M34, M36, M37 and M38 are all on the oldest-20 list, but M35 is not ?????

I think something needs repair. The top-5000 list I downloaded on "Sat Jun 9 18:50:25 CDT 2007" shows

Code:
   73  149797*2^1414137-1
   74  2^1398269-1
   75  192089*2^1395688-1
but the one at http://primes.utm.edu/primes/lists/all.pdf with time "Wed Aug 6 20:21:04 CDT 2008" has

Code:
105  149797 * 2^1414137 -1
106  127 * 2^1398889 - 1
107  1564347 * 2^1398269 - 1
109  192089 * 2^1395688 - 1
Rank #108 (where M35 belongs) is missing.

I've sent an e-mail to Chris Caldwell.

- - -

Correcting this will push one of the non-Mersennes off the oldest-20 list.

Last fiddled with by cheesehead on 2008-08-07 at 02:12
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Old 2008-08-07, 02:17   #3
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Oh, cool! I thought the linked search was just an interesting list of old primes. Glad to see it was actually useful as an error check.
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Old 2008-08-07, 05:43   #4
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Quote:
Originally Posted by cheesehead View Post
M32, M33, M34, M36, M37 and M38 are all on the oldest-20 list, but M35 is not ?????

I've sent an e-mail to Chris Caldwell.

- - -

Correcting this will push one of the non-Mersennes off the oldest-20 list.
Fixed as of the time of this posting.
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Old 2008-08-07, 15:20   #5
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http://primes.utm.edu/primes/search.php?MinAge=2865
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Old 2008-08-07, 17:13   #6
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Why the prevalence of k2^n + 1 over k2^n - 1
among non-Mersennes?

Last fiddled with by davieddy on 2008-08-07 at 17:17
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Old 2008-08-07, 23:46   #7
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Caldwell replied that what I noticed was an unintended side effect of verifications he was performing. "But, as you noticed, if you downloaded while it was verifying, then it did not show on the list. I'll fix that."

However, what I actually reported to Caldwell was that M35 was missing from http://primes.utm.edu/primes/lists/all.pdf. I didn't mention that it was missing from http://primes.utm.edu/primes/search.php?MinAge=2860. I suppose his fix covered that, too.

Last fiddled with by cheesehead on 2008-08-08 at 00:11
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Old 2008-08-08, 00:13   #8
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Quote:
Originally Posted by masser View Post
Note that http://primes.utm.edu/primes/search.php?MinAge=2860 and http://primes.utm.edu/primes/search.php?MinAge=2865 give slightly different results (as of the time I post this).

Perhaps what you're getting is not the 20 oldest primes on the Top 5000 list, but the 20 largest primes older than 2860, or 2865, days, respectively? In that case, a few days from now http://primes.utm.edu/primes/search.php?MinAge=2860 and http://primes.utm.edu/primes/search.php?MinAge=2865 may return identical results.

Last fiddled with by cheesehead on 2008-08-08 at 00:24
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Old 2008-08-25, 00:25   #9
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Quote:
Originally Posted by cheesehead View Post
In that case, a few days from now http://primes.utm.edu/primes/search.php?MinAge=2860 and http://primes.utm.edu/primes/search.php?MinAge=2865 may return identical results.
... and so they do, now.
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Old 2008-08-27, 12:31   #10
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Quote:
Originally Posted by davieddy View Post
Why the prevalence of k2^n + 1 over k2^n - 1
among non-Mersennes?
I believe that the programmes available at that time did not favour -1 cases. LLR came much later.
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