- http://www.utm.edu/research/primes/ Chris Caldwell's webpage on prime numbers records, research, etc.
- http://www.learnstuff.com/integer-sequence-resources/ Integer Sequence Resources.
- http://www.math.niu.edu/~rusin/known-math/welcome.html Dave Rusin's Mathematical Atlas.
- http://www.shyamsundergupta.com/ Shyam Sunder Gupta's Number Recreations.

[the following was added May 2001]
**RSA Security, has revamped its Factoring Challenges.**

Prizes now start at US$10,000 (factorization of a 576 bit modulus) to US$200,000 (factorization of a 2048 modulus).

RSA and its predecessor companies have been sponsoring factorization challenges for many years, but until now the prize money has been nominal. It is hoped that the increased bounties will draw more people to the field, and spur new research.

For details, including the challenge numbers, see:

http://www.rsasecurity.com/rsalabs/challenges/factoring/index.html

Peter Trei, Cryptoengineer, RSA Security Inc., ptrei@rsasecurity.com

**Breaking News (in November of
2000): 233-digit SNFS factorization**

*The Cabal *announces the completion, on November 14, 2000, of
the factorization with the *Special Number Field Sieve*(SNFS) of the
233-digit
Cunningham
number 2^773 + 1 into the product the numbers 3 and 533371 and three
primes of 55, 71, and 102 digits, respectively. This establishes
a new record for the Special Number Field Sieve. [Note that this
is somewhat easier to factor than a number of this size which is the product
of only two primes of approximate equal size. In this case the 3
and 533371 factors were easy to find. And the remaining factor has
the small 55-digit and 71-digit primes.]

The sieving was done on about 150 SGI workstations and Sun workstations
and servers running at 180-450 MHz, and on about 100 PCs running at 266-600
MHz. The sieving took about five calendar months. It was started mid-April,
2000, and finished on September 15, 2000. **Total sieving time was 57.4
CPU years.**

The previous SNFS record was the 211-digit repunit number 10,211- = (10^211 - 1)/9, factored on April 8, 1999, also by the Cabal.

Factorization details are available from: ftp://ftp.cwi.nl/pub/herman/SNFSrecords/SNFS-233.

**Maple Worksheets:** Students
may download the following Maple worksheets. To do so hold down the right
mouse button (on a **Mac** just hold down the single mouse button) the
select **Download file to disk** or **Save file to Disk**. Then you
should be able to open the file with Maple. You might open Maple first
and then while in Maple choose **Open** from the **File** menu item.

**RSA
Examples with Maple**
**Maple
Introduction for Number Theory**