Open directory - Combinatorics - Math

Algebraic Combinatorics via Finite Group Actions - A hypertext by A. Betten, H. Fripertinger and A. Kerber.

ArXiv Front: CO Combinatorics - Combinatorics section of the Front for the Mathematics ArXiv.

Catalogue of Lattices - A catalogue of different types with applications to packing spheres by Neil Sloane and Gabriele Nebe.

CATS: Combinatorial Algorithms Test Sets - Searchable index of problems, links and methodology maintained by the Association for Computing Machinery.

Combinatorial Catalogues - Combinatorial objects such as graphs, designs and geometries collected by Gordon Royle.

Combinatorial Data - Brendan McKay's collection of miscellaneous tables in graph6 or sparse6 format.

The Combinatorial Object Server - Select a type together with specific parameter values and COS will return a list of all such combinatorial objects.

Combinatorics - Subfields in the AMS MSC 2000 classification 05.

Combinatorics - MathWorld article with basic definitions and links.

The Combinatorics Net - Maintained by Bill Chen.

Counting Young Tableaux - An article on counting Young tableaux of bounded height by François Bergeron and Francis Gascon.

The Cutting Sticks Problem - An unsolved combinatorial problem by Frans Faase.

Encyclopedia of Combinatorial Structures - Searchable database of structures with specifications and counts.

Enumeration of Polyhedra - Enumeration of polyhedra with upto 9 faces by Steven Dutch.

Enumeration of the Binary Trees - A note on Catalan numbers by Ivan Galkin.

Extremal Combinatorics - With Applications in Computer Science by Stasys Jukna.

Generating Functions - Introduction to generating functions with interactive java applets by Alexander Bogomolny.

G-Systems - Theory of chord structures to create music through algorithms by Vladimir Ladma.

Lectures in Combinatorics - An introduction to partially ordered sets, Dilworth's theorem, lattices and combinatorial geometries.

The Math Forum Math Library - Combinatorics - Comprehensive catalog of websites relating to Combinatorics.

A New Proof of the Four Colour Theorem - By Ashay Dharwadker. Includes profile, research papers for other algorithms, lecture notes, and student database.

On-line Dictionary of Combinatorics - An expanding web text by Joe Fields.

Polya's Enumeration Theorem - An article on generating functions and Polya's theory of counting by Karl Dahlke.

Series Expansions - Iwan Jensen counts polyominoes (aka lattice animals), paths, and various related quantities.

The Seventeen Wallpaper Groups - Examples in traditional Japanese patterns.

Squared Squares - Tilings of squares and rectangles, the classical problem and variations.

A Survey of Venn Diagrams - Various facts and figures about Venn diagrams by Frank Ruskey.

Topics in Mathematics - Combinatorics - In the Mathematics Archive at University of Tennessee, Knoxville.