Absolutely Abnormal Numbers
Published as math.NT/0006089, this note investigates numbers that are normal to no base whatsoever, and writes down explicitly such a number.
Ask Dr. Math: History of the Terms Google and Googleplex
Explains how these very large numbers (1 followed by a hundred zeroes, and 1 followed by a google of zeroes, respectively) were named. With links to references. From Swarthmore's D…
Catalan Number -- MathWorld
Illustration of the Catalan numbers related to Euler's polygon division problem.
Harry J. Smith's Fun With Mathematics
Fun math stuff, including computing pi, perfect numbers, Fibonacci numbers, the tesseract, a look into 4-dimensional space.
Mathematical Constants and Computation
Essays, references, links, software.
RJN's More Digits of Irrational Numbers
Several million digits of e, and the square roots of 2, 3, 5, 6, 7, 8, and 10.
Triangular Numbers
Properties of triangular numbers including reversible, happy, harshad, highly composite, deficient, abundant ones.
Verbose.net
Dedicated to the natural order of the universe and to the irrational and logical chaos it presents.
Wikipedia - Mathematical constant
A list of constants with links to more detailed information.
World of Numbers
Contains a collection of randomly gathered numbers, curios, puzzles, palindromes and primes.