Typo in reported factor?

[R.D. Silverman]

Bruce reports finding a factor of 6^391-1 on the ECMNET webpage.

But unless my software is really screwing up, the factor does
not divide. I am guessing that one or more digits are missing?

[Batalov]

Yep, it is 7,359-.
Cofactor c224 is composite.

(It must have divided a number from the list because othewise Paul's form wouldn't accept it. This sudoku puzzle was easy.)

[bdodson]

Originally Posted by Batalov

Yep, it is 7,359-.
Cofactor c224 is composite.

(It must have divided a number from the list because othewise Paul's form wouldn't accept it. This sudoku puzzle was easy.)

Yes, sorry; and thanks. Different c27x first five hole. But another
small one; seems likely that there are more to find. Too many new
inputs over the weekend, when many of the labs are closed. Distracted
by exam grading and _three_ new top5000 Proth primes. Plus the wind
knocked out our power for two hours here today.
Regards, Bruce
---

[bdodson]

Originally Posted by Batalov

(It must have divided a number from the list because othewise Paul's form wouldn't accept it. This sudoku puzzle was easy.)

OK, how's about this one?
474942339376967475871960321762614254290810243038880418971061342256529

2nd hole. -bd

[Batalov]

A hole in one. Now, this is not a futile factor. :-)

Congratulations!

[bdodson]

Originally Posted by Batalov

A hole in one. Now, this is not a futile factor. :-)

Congratulations!

Here's the group order:

Magma V2.16-4     Mon Feb 21 2011 09:16:48 on altair1  [Seed =3370645033]

[ <2, 2>, <3, 2>, <7, 2>, <11, 2>, <53, 1>, <353, 1>, <467, 1>, <779591,1>,
<1057367, 1>, <15751453, 1>, <40771103, 1>, <43303219, 1>, <356236847,1>,
<31186368729239, 1> ]

So that's p = 356236847 < 400M = B1 for the step1 prime,
q = 31186368729239 > 1.59e13 = B2 for the step2. Ooops. If it matters,
this ran with k = 20. Sounds like this really used some GMP-ECM features;
and I was more than just lucky with the parameters!

Bruce (This is the new p69 by ecm, from 2,1822L C197.)