20190509, 04:34  #1 
Apr 2019
5·41 Posts 
Factoring small composites
I was considering trying to factor some composites from the Downloads > "List of 1.000 randomly chosen, small composite numbers"
Is this useful to the overall purpose of factordb to fully factor these small composites? Also is there any particular script or program I can use to only evaluate the expressions created by this, and spit them into a simple file of decimal numbers by line, so I can more easily test with various programs? 
20190509, 20:11  #2  
Mar 2018
129_{10} Posts 
Quote:
Nobody is specifically waiting for them – and if someone is, they are wrong to do so, because factordb isn't and shouldn't be a treated as a free factoring service. Anyone is better off factoring numbers themselves than submitting them to FDB and waiting for them to be factored. Unfortunately, it kinda gets used like that by whoever since it's so open. There's a lot of "garbage" composite numbers that people might've not even submitted consciously, but just looked up some formulae. I've downloaded that list right now and i see it has 91 and 92digit numbers. You can see how many total there are here. Quote:


20190510, 05:15  #3 
Romulan Interpreter
Jun 2011
Thailand
22231_{8} Posts 
There is a "yoyo" perl script somewhere, who does a wonderful job. This script takes a random composite from the db and factors it using yafu (or other external tool) then it reports the result to the db. It is nice in sense that it is "set it and forget it", and you can also specify the desired digit and from where the random composite is taken (like "get a 120digits composite from the smallest 100 numbers which are 120digit composites). The "randomness" is to avoid duplication of work  it still happens sometime because people want to factor "the smallest composite available" and fdb does not have an assignment procedure, but the probability is low. Of course, you must have installed some perl, and some factoring tool, like yafu.
You can search the forum for yoyo.pl or so, and if you can't find it, I will post it soon when I get home (I do not have it here at job). Last fiddled with by LaurV on 20190510 at 05:15 
20190510, 06:56  #4 
Mar 2018
129_{10} Posts 
Small correction. FDB doesn't actually have an ordinality of numbers with the same digit count (by, erm, the numbers themselves). All the outputs in the same digit size are arbitrarily random. So you cannot get "smallest" 120digits, for example. However, they are always essentially in the same order – the order they are read from the DB. So those scripts randomize that – the "page" from which the numbers are taken.

20190510, 10:30  #5  
Oct 2006
Berlin, Germany
2^{2}·3^{2}·17 Posts 
Quote:


20190510, 16:02  #6 
Sep 2009
2,027 Posts 
It's at http://mersenneforum.org/showthread.php?t=19232&page=3 post 25.
Note you must change factorization.ath.cx to factordb.com since the old DNS entry doesn't work now. Chris 
20201101, 17:31  #7  
Sep 2009
2,027 Posts 
Quote:
Quote:
Chris 

20201101, 19:43  #8 
"Garambois JeanLuc"
Oct 2011
France
1052_{8} Posts 
Page updated, but only for bases 2, 3, 20, 21, 23, 162, 439, 496.
31^36 and complete base 385 are reserved for me. Thanks to all for your help ! Please check if all your requests have been taken into account. The other bases will be updated in the next few weeks, as it takes a lot of time for each base . 
20201102, 13:18  #9 
"Ed Hall"
Dec 2009
Adirondack Mtns
3·1,229 Posts 
Note: Post was edited to remove thread irrelevant content from this copied post. Original content can be found here.
@chris2be8: I wonder if the large number of small composites on factordb was just a result of the rebuild. I did factor a few thousand, but quickly got close to the hour's limit for a couple values. They seemed to be clearing pretty fast at the time, so I left the rest alone. Last fiddled with by EdH on 20201104 at 18:35 
20201102, 17:13  #10 
Sep 2009
2,027 Posts 
I don't think the small composites are from the rebuild. I've seen quite a few numbers like:
Code:
(738468*49##+557)/35840141013305049257323 (2^295+94923)/13352559799576307 Chris 
20201102, 17:37  #11  
"Ed Hall"
Dec 2009
Adirondack Mtns
3×1,229 Posts 
Quote:


Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Is there a tool that picks off small composites constantly?  fivemack  FactorDB  14  20180207 17:00 
Commandline program for factoring small numbers  James Heinrich  Software  22  20110829 16:35 
What's the point of factoring known composites?  ixfd64  PrimeNet  4  20110221 11:51 
A small factoring program  Yamato  Factoring  2  20071121 23:29 
Factoring of composites with near factors  request for data  AntonVrba  Factoring  3  20060205 06:30 