Links and subcategories within the Number Theory section are provided below.
Directory Links:
Dave Rusin's guide to number theory. Link: http://www.math.niu.edu/~rusin/knownmath/index/11XX.html

transformations of relatively prime pairs, representation as sum of two squares, divisors of n*n+1 Link: http://www.hbmeyer.de/taupaeng.htm

A mathematics textbook in Number Theory for advanced undergraduate or beginning graduate students; an ebook in PDF format without DRM Link: http://www.trillia.com/mosernumber.html

Australian Numerals replace Hindu Arabic and Roman Numerals as an easier way to do mathematics Link: http://australiannumerals.org/AustralianNumeralsExplained.html

Lecture notes by Alain Connes. Link: http://www.math.ohiostate.edu/lectures/connes/Connes_course.html

A unified approach to covering systems, restricted sumsets and zerosum problems by ZhiWei Sun. Link: http://math.nju.edu.cn/~zwsun/csz.htm

With notes on Carmichael numbers and the life of R.D. Carmichael. Link: http://www.pballew.net/FermLit.html

Some notes from the MIT collection. Includes Gosper's algorithms for CF arithmetic. Link: http://www.inwap.com/pdp10/hbaker/hakmem/cf.html

To determine linear integer dependence among numerical constants and to determine the minimal polynomial of an approximate algebraic number. Interactive or via email. Link: http://oldweb.cecm.sfu.ca/~aszanto/IntegerRelations

A web article with a brief history and account of their relationship with the Riemann zeta function and Fermat's Last Theorem (HTML/PS). Link: http://numbers.computation.free.fr/Constants/Miscellaneous/bernoulli.html
