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Search: Posts Made By: sean
Forum: Factoring 2020-12-14, 20:28
Replies: 9
Views: 675
Posted By sean
Since no one else has replied. Way back in the...

Since no one else has replied. Way back in the 1990s, I maintained a collection of abstracts in the field of cryptography -- if you try really hard you might still be able to find traces of it. ...
Forum: Factoring 2020-11-03, 20:06
Replies: 507
Views: 71,192
Posted By sean
Congratulations. For a moment I thought you had...

Congratulations. For a moment I thought you had done the leading edge, but it is still nice to have this one done as well. So I see EM49 is now the smallest not completely factored number in this...
Forum: Factoring 2020-06-29, 03:18
Replies: 148
Views: 27,936
Posted By sean
I'm not sure what you mean by this. All the...

I'm not sure what you mean by this. All the places I checked refer to these as the
Wolstenholme numbers.
Forum: Factoring 2020-03-21, 04:08
Replies: 507
Views: 71,192
Posted By sean
Thanks and congratulations! One less of these...

Thanks and congratulations! One less of these for me be hitting with ECM. It's quite big step to the next smallest:

For 145!-1 I have done 12335 curves with B1=850M.

Smallest composites:
...
Forum: Factoring 2020-02-19, 20:17
Replies: 419
Views: 48,740
Posted By sean
I completed the above by GNFS and pushed it a few...

I completed the above by GNFS and pushed it a few more steps. HP146 is now stuck on a C177, but I have only done minimal ECM in an attempt to break it (t45 level).
Forum: Factoring 2019-09-30, 19:57
Replies: 148
Views: 27,936
Posted By sean
Thanks! I'll look to do some of these next cases...

Thanks! I'll look to do some of these next cases by SNFS at some point, but my resources are not what they once were.
Forum: Factoring 2019-09-23, 21:45
Replies: 148
Views: 27,936
Posted By sean
I've submitted a b-file for A246556 up to an...

I've submitted a b-file for A246556 up to an including a(612).
Forum: Factoring 2019-09-23, 21:18
Replies: 148
Views: 27,936
Posted By sean
The most interesting cases in the OEIS wanted...

The most interesting cases in the OEIS wanted numbers list are those marked "*". They correspond to sequences where only a few terms are known (e.g. not enough to fill the usual data lines in the...
Forum: Factoring 2018-09-19, 21:19
Replies: 41
Views: 4,111
Posted By sean
The sum starting from 0 is sometimes denoted !n,...

The sum starting from 0 is sometimes denoted !n, the sum starting from 1, K(n). See early results at http://www.asahi-net.or.jp/~KC2H-MSM/mathland/matha1/. I believe all those have been moved to...
Forum: Factoring 2018-07-01, 19:22
Replies: 507
Views: 71,192
Posted By sean
Very impressive, shame you didn't get a slightly...

Very impressive, shame you didn't get a slightly larger penultimate.
Forum: Factoring 2018-05-16, 21:34
Replies: 3
Views: 1,021
Posted By sean
If you want easy numbers to start with visit: ...

If you want easy numbers to start with visit:

http://factordb.com/listtype.php?t=3&mindig=110&perpage=1000&start=0

You can change the 110 to whatever size you want. As you factor numbers you...
Forum: FactorDB 2018-05-04, 20:52
Replies: 458
Views: 53,919
Posted By sean
I think there are others higher up as well. My...

I think there are others higher up as well. My efforts to sweep downwards from 120 digit numbers also periodically hit them. Unfortunately, I haven't been able to isolate any of the higher ones to...
Forum: FactorDB 2018-03-01, 21:53
Replies: 458
Views: 53,919
Posted By sean
Finally back down below 500,000 composites <= 120...

Finally back down below 500,000 composites <= 120 digits. The C100s still look like a formidable barrier.
Forum: FactorDB 2018-03-01, 21:51
Replies: 2
Views: 2,740
Posted By sean
I'm opposed to this idea. In the few cases where...

I'm opposed to this idea. In the few cases where it might actually be interesting you can construct a more useful algebraic expression of the form M(n+1) * 10^k + M(n) where k is the decimal length...
Forum: Factoring 2017-12-18, 20:19
Replies: 507
Views: 71,192
Posted By sean
Yes, it is the same me. There is no longer a...

Yes, it is the same me. There is no longer a website devoted to the factorial numbers -- in fact the ECMNET page still attempts to link to your old non-existent page. I have files with all the...
Forum: Factoring 2017-12-06, 09:26
Replies: 507
Views: 71,192
Posted By sean
My total curves on 139!+1 are 6285 at B1=850M...

My total curves on 139!+1 are 6285 at B1=850M (including those I previously reported). I'll stop work on this number now.
Forum: FactorDB 2017-11-12, 22:05
Replies: 458
Views: 53,919
Posted By sean
I've looked at a few of the what looks like...

I've looked at a few of the what looks like useless C100s that someone added (i.e. those with id's starting around 1100000000968200000). I factored a few with near id's in the hope of observing a...
Forum: YAFU 2017-10-14, 02:30
Replies: 7
Views: 1,920
Posted By sean
Ok. Thanks for all the comments. I can complete...

Ok. Thanks for all the comments. I can complete the C145 by GNFS easy enough. Its the first time I've actually had a problem like this happen with yafu, and on the whole I find it reliable.
Forum: YAFU 2017-10-13, 18:21
Replies: 7
Views: 1,920
Posted By sean
Thanks for this suggestion. I haven't used msieve...

Thanks for this suggestion. I haven't used msieve directly much. The files I have left over from yafu (other than various logs) are just:

-rw-rw-r-- 1 sean rtg 463 Sep 19 22:23 nfs.job...
Forum: YAFU 2017-10-13, 09:08
Replies: 7
Views: 1,920
Posted By sean
Resume dependency processing?

I'm trying to factor the C195 cofactor of Pell(583) by SNFS using Yafu. All the sieving completed, linear algebra completed, and it produced a 51-digit prime factor from dependency 2, but left a...
Forum: Factoring 2017-09-26, 21:46
Replies: 507
Views: 71,192
Posted By sean
I've done 5326 curves with B1=850M on 139!+1. ...

I've done 5326 curves with B1=850M on 139!+1. It's slow progress but better than nothing.
Forum: Factoring 2017-09-26, 18:41
Replies: 507
Views: 71,192
Posted By sean
Nice. There are currently now only 3 factorial...

Nice. There are currently now only 3 factorial numbers with cofactors less than C200: 167!-1 C181, 145!-1 C185, and 169!+1 C193. Of these, I've done the most ecm on 145!-1 (t55 done, plus some of...
Forum: Factoring 2017-09-14, 04:52
Replies: 2
Views: 1,162
Posted By sean
Iteration of (sigma(n)+phi(n))/2

In recent weeks there has been some interest on the seqfan mailing list about iterating the map (sigma(n)+phi(n))/2 (see for example A291790 (https://oeis.org/A291790)).

In many cases the map...
Forum: FactorDB 2017-09-11, 18:57
Replies: 458
Views: 53,919
Posted By sean
That's me. I picked a particular size and tried...

That's me. I picked a particular size and tried harder on those. It taken a few months to get it that low.
Forum: YAFU 2017-05-18, 04:14
Replies: 22
Views: 3,141
Posted By sean
Excellent. I can confirm removing the m line...

Excellent. I can confirm removing the m line solves the problem. Nice to know that I no longer need to calculate that externally. Many thanks to all who helped with this.
Showing results 1 to 25 of 221

 
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