Top of page Bottom of page

Home Windows 10 Windows 7 Sydney PC&TUG Web Design Primes Factors Factor Records Nice Split Digital Photos Links Downloads Archives Contact Us


Search this site only

• Recent Factors

Oct 16, 2019
10213 - 4 • 10106 - 1  [910659106]c204 3556373425­5761697956­0177337535­1953339436­7900911749­1<p51>
Oct 15, 2019
55 • 10215 + 71  [612149]c204 7326186558­9019150426­6229436843­7735306016­2581916072­8674186308­9746404979­0292618551­6138386323­9<p91>
Oct 14, 2019
85 • 10216 + 23  [942157]c204 3880059272­3286257787­8033595615­3209914470­991293619<p49>
Oct 13, 2019
26 • 10217 - 71  [282161]c204 4318405152­4837884287­3699335407­0631539476­214181<p46>
Oct 11, 2019
10215 - 3  [92147]c204 1182894261­4336317533­6194385664­4401596070­6815142113­1184928608­4130757<p67>

• Other Topics

Using exponents up to 100,000, primes of the form k • 2n ± 1 were calculated using the latest version of the free OPENpfgw program available from SourceForge.

More photos have been added. See our friend Bill G and a "floating ship" which appears to hang suspended above the horizon.

See some screen-shots of Windows 7. 

See screen-shots of various Insider Builds of Windows 10. 

See interesting shapes created just using CSS code.

See my personal Blog: bobb777 and the Blog of the Sydney PC User Group: sydneypcug.

The latest addition is an Unscramble program to solve Jumble™ puzzles.

The Sydney PC User Group is an independent club of users discussing all aspects of personal computers.

The members also help each other solve computer problems.  It has several Special Interest Groups or SIGs including Genealogy, Digital Photography and Web Design.

This web-page was initially written with NetObjects Fusion, one of the programs used by the Web Design SIG.  See the Reports for recent meeting information.

More recently I've written some Perl scripts to construct web-pages based on tables of integer factors that I have discovered.

Use the inbuilt DOS ftp command to upload files quickly from a batch file.  If uploading different files each time, however, use a Windows FTP program like the free Core-FTP program instead.

Read the details in this short tutorial.

See what soft hyphens are all about.  Enable Javascript and check out your browser by loading this test page.  We check the Windows version of Apple's Safari browser.

Unicodes may be necessary in HTML when named symbols are not available (for Cyrillic characters Я and и for example).

Check that you have valid HTML or XHTML code online using the World Wide Web Consortium (W3C) official site or offline using the free  CSE HTML Validator Lite program.

The year 2015 sees the culmination of a four and a half-year project to factor seventeen very large Cunningham numbers.

A technique was used where the sieving data was re-used by the authors Thorsten Kleinjung, Joppe W. Bos, and Arjen K. Lenstra, described in their paper, published on January 12, 2015.

[1] A 119-digit personal record prime factor has been found on Tue Mar 19th, 2019.  It divides the 241-digit number 10241 + 63 • 10120 - 1 = p119 (125301...) • p122.

[2] A 116-digit personal record prime factor has been found on Wed Feb 15th, 2017.  It divides the 233-digit number 5 • 2790 + 1 = p116 (302521...) • p117.

[3] A 116-digit personal record prime factor has been found on Fri Feb 22nd, 2019.  It divides the 240-digit number 23 • 10239 - 11 = p116 (205789...) • p125.

[4] A 112-digit personal record prime factor has been found on Fri April 1st, 2016.  It divides the 226-digit number 7 • 2746 + 1 = p112 (844194...) • p114.

Work is progressing on factorising numbers of the form k • 2n ± 1 with k (odd) from 3 to 15 and n ≤ 1000.  The results are recorded by Mikael Klasson.

Msieve, written by Jason Papadopoulos is described.  It contains fast code to solve large sets of linear equations.  See the new Perl script to automate Msieve post-processing after a GGNFS run.

Updated: Wed Oct 16, 2019
© 2019 Bob Backstrom
Home Windows 10 Windows 7 Sydney PC&TUG Web Design Primes Factors Factor Records Nice Split Digital Photos Links Downloads Archives Contact Us