Twenty Oldest Primes on Top 5000 List
 

[url]http://primes.utm.edu/primes/search.php?MinAge=2860[/url]

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
[/code]

but the one at [URL]http://primes.utm.edu/primes/lists/all.pdf[/URL] 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[/code]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.

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.

[QUOTE=cheesehead;138896]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.[/QUOTE]
Fixed as of the time of this posting.

New Link
 

[url]http://primes.utm.edu/primes/search.php?MinAge=2865[/url]

Why the prevalence of k2^n + 1 over k2^n - 1
among non-Mersennes?

Caldwell replied that what I noticed was an unintended side effect of verifications he was performing. "[COLOR=#0000ff]But, as you noticed, if you downloaded while it was verifying, then it did not show on the list. I'll fix that.[/COLOR]"

However, what I actually reported to Caldwell was that M35 was missing from [URL="http://primes.utm.edu/primes/lists/all.pdf"][COLOR=#22229c]http://primes.utm.edu/primes/lists/all.pdf[/COLOR][/URL]. I didn't mention that it was missing from [URL]http://primes.utm.edu/primes/search.php?MinAge=2860[/URL]. I suppose his fix covered that, too.

[quote=masser;138928][URL]http://primes.utm.edu/primes/search.php?MinAge=2865[/URL][/quote]Note that [URL]http://primes.utm.edu/primes/search.php?MinAge=2860[/URL] and [URL]http://primes.utm.edu/primes/search.php?MinAge=2865[/URL] give slightly different results ([I]as of the time I post this[/I]).

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 [URL]http://primes.utm.edu/primes/search.php?MinAge=2860[/URL] and [URL]http://primes.utm.edu/primes/search.php?MinAge=2865[/URL] may return identical results.

[quote=cheesehead;138963]In that case, a few days from now [URL]http://primes.utm.edu/primes/search.php?MinAge=2860[/URL] and [URL]http://primes.utm.edu/primes/search.php?MinAge=2865[/URL] may return identical results.[/quote]... and so they do, now.

[QUOTE=davieddy;138932]Why the prevalence of k2^n + 1 over k2^n - 1
among non-Mersennes?[/QUOTE]

I believe that the programmes available at that time did not favour -1 cases. LLR came much later.