M39761383 history
 

One of my machines recently finished a double check and apparently
the residue did not match. I go look at the details for this exponent

[url]http://www.mersenne.org/report_exponent/?exp_lo=39761383&full=1[/url]

and it has had three LL tests run and none of the residues match.
Does this happen a lot?

Trivia question: Which exponent has had the most number of
(unmatching residue) LL tests done on it? (I don't know.)

It happens often enough. It's not unusual to need a quad check.

Most or all of those questions have been answered at some point in time in this thread: [url]http://mersenneforum.org/showthread.php?t=20372[/url]

Of course, I couldn't tell you *where* in the thread the answers lie. Perhaps madpoo would have better luck refreshing our memories.

Suffice it to say, as Mark indicates, quad checks are surprisingly common, I think more than 10 per 1M exponent range, possibly even up to a hundred.

I think the most mismatches is somewhere around 6, though I may be recalling incorrectly.