M39761383 history

bgbeuning · 2016-01-29, 03:02

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

http://www.mersenne.org/report_expon...9761383&full=1

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.)

Mark Rose · 2016-01-29, 03:08

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

Dubslow · 2016-01-29, 03:19

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

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.

2016-01-29, 03:02	#1
bgbeuning Dec 2014 3×5×17 Posts	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 http://www.mersenne.org/report_expon...9761383&full=1 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.)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
A question of history	devarajkandadai	Number Theory Discussion Group	8	2017-06-01 13:15
Cranks of History	TimSorbet	Miscellaneous Math	1	2016-04-01 12:36
History	ET_	Operazione Doppi Mersennes	15	2012-09-19 13:11
History	Greenbank	Octoproth Search	1	2007-02-16 23:41
History of 3*2^n-1	Citrix	3*2^n-1 Search	2	2006-11-16 00:13

2016-01-29, 03:08	#2
Mark Rose "/X\(‘-‘)/X\" Jan 2013 2²·3·7·37 Posts	It happens often enough. It's not unusual to need a quad check.

2016-01-29, 03:19	#3
Dubslow Basketry That Evening! "Bunslow the Bold" Jun 2011 40<A<43 -89<O<-88 7221₁₀ Posts	Most or all of those questions have been answered at some point in time in this thread: http://mersenneforum.org/showthread.php?t=20372 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.