Solves quadratic Diophantine equations (integer equations of the form a x^2 + b xy + c y^2 + dx + ey + f = 0). Now it includes the source code.

Ulam's Spiral (updated Mar 25th, 2004)

Java applet featuring a graphical view of prime numbers.

Factorization using the Elliptic Curve Method (ECM) (updated October 16th, 2003)

Applet that can be used to find 20- or 30-digit factors of numbers or numerical expressions up to 1000 digits long. It also computes the number and sum of divisors, Euler's totient and Moebius, and its decomposition as a sum of up to 4 perfect squares.

Discrete logarithm calculator (updated March 30th, 2002)

Applet that finds the exponent in the expression Base^Exponent = Power (mod Modulus).