East Side, West Side Lecture notes by Herbert S. Wilf on generating combinatorial objects and Maple. http://www.cis.upenn.edu/~wilf/lecnotes.html

The Cutting Sticks Problem An unsolved combinatorial problem by Frans Faase. http://home.wxs.nl/~faase009/cutsticks.html

CADCOM Committee for the Advancement of Discrete and Combinatorial Mathematics. http://www.dms.auburn.edu/~rodgec1/cadcom/

British Combinatorial Committee Conference listings, bulletin and links maintained by Peter Cameron. http://www.maths.qmw.ac.uk/~pjc/bcc/

The Combinatorics Net Maintained by Bill Chen. http://www.combinatorics.net/

ArXiv Front: CO Combinatorics Combinatorics section of the Front for the Mathematics ArXiv. http://front.math.ucdavis.edu/math.CO

SIAM Activity Group on Discrete Mathematics Provides an opportunity to unify pure discrete mathematics and areas of applied research. http://www.siam.org/siags/siagdm.htm

Enumeration of the Binary Trees A note on Catalan numbers by Ivan Galkin. http://ulcar.uml.edu/~iag/CS/Catalan.html

The Combinatorial Object Server Select a type together with specific parameter values and COS will return a list of all such combinatorial objects. http://www.theory.csc.uvic.ca/~cos/

Topics in Mathematics - Combinatorics In the Mathematics Archive at UTK. http://archives.math.utk.edu/topics/combinatorics.html

Extremal Combinatorics With Applications in Computer Science by Stasys Jukna. http://www.thi.informatik.uni-frankfurt.de/~jukna/EC_Book/

Encyclopedia of Combinatorial Structures Searchable database of structures with specifications and counts. http://algo.inria.fr/encyclopedia/

Combinatorial Catalogues Combinatorial objects such as graphs, designs and geometries collected by Gordon Royle. http://www.cs.uwa.edu.au/~gordon/data.html

Algebraic Combinatorics via Finite Group Actions A hypertext by A. Betten, H. Fripertinger and A. Kerber. http://www.mathe2.uni-bayreuth.de/frib/html/book/hyl00.html

CATS: Combinatorial Algorithms Test Sets Searchable index of problems, links and methodology maintained by the Association for Computing Machinery. http://www.jea.acm.org/CATS/

Amazing Mathematical Object Factory Generators for several basic combinatorial objects by Frank Ruskey and Scott Lausch. http://www.schoolnet.ca/vp-pv/amof/

A Survey of Venn Diagrams Various facts and figures about Venn diagrams by Frank Ruskey. http://www.combinatorics.org/Surveys/ds5/VennEJC.html

G-Systems Theory of chord structures to create music through algorithms by Vladimir Ladma. http://www.sweb.cz/vladimir_ladma/english/music/articles/dide99.htm

Combinatorics Subfields in the AMS MSC 2000 classification 05. http://www.ams.org/msc/05-xx.html

Combinatorial Data Brendan McKay's collection of miscellaneous tables in graph6 or sparse6 format. http://cs.anu.edu.au/~bdm/data/