Not sure I should have this DC....
 

[CODE]Exponent Status Data
18728873 No factors below 2^67
P-1 B1=225000, B2=4500000
Unverified LL 46D44BAAF2DE42__ by "Ezram van Rijnberk"
Unverified LL 9FF61215444796__ by "Stefan Klinke"
Unverified LL FB879860A8D339__ by "petrw1" on 2008-12-21
Assigned Double-checking to "petrw1" on 2008-12-21
History FB879860A8D339__ by "petrw1" on 2008-12-21 [/CODE]

Three LL's/DC's. Three different residues. That alone is a concern.

But, one DC was mine and it is back assigned to me to DC again. Should I release it?

What is normally considered "good pratice" is to have, for a given exponent, the first time test and the DC perfomed by different participants.
So I would say "yes, release it".

The use, since several versions ago, of a pseudorandom bit-shift at the beginning (and reversal at the end) provides noticeable protection against faulty hardware's producing the same erroneous residue from the same cause during two successive L-Ls on the same system. So there is not quite the same suspicion of same-system results that there had been before. However, there are still sources of error that would not be affected by that bit-shift.

IIRC v4 reports showed that shift count along with the returned residue.

[QUOTE=cheesehead;157618]The use, since several versions ago, of a pseudorandom bit-shift at the beginning (and reversal at the end) provides noticeable protection against faulty hardware's producing the same erroneous residue from the same cause during two successive L-Ls on the same system. So there is not quite the same suspicion of same-system results that there had been before. However, there are still sources of error that would not be affected by that bit-shift.

IIRC v4 reports showed that shift count along with the returned residue.[/QUOTE]

So are you implying I should or should not drop it OR it doesn't really matter anymore?

[quote=petrw1;157643]So are you implying I should or should not drop it OR it doesn't really matter anymore?[/quote]Be above suspicion, like Caesar's wife. ([url]http://www.brainyquote.com/quotes/quotes/j/juliuscaes161092.html[/url])

Drop it like a hot potato.

Hereby dropped....

I searched the double-checked results for exponents above 40M. There where quite a lot double checked by the same user and sometimes the same computer. Some of the results are obviously multiple submissions of the same result... See the attached file.

Jacob

[quote=S485122;157675]quite a lot double checked by the same user and sometimes the same computer[/quote]Caesar would've ordered them to be DCed independently ... or else divorced them.

And those exponents are lucky that Caesar was not like Henry VIII...