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**Generic Two integer variable equation solver:**Diophantine equation**ax**solver, where the unknowns^{2}+ bxy + cy^{2}+ dx + ey + f = 0**x**and**y**can be integer numbers only. Written in Java/JavaScript. Last updated on May 31st, 2001.**Quadratic modular equation solver:**Calculator that can solve equations of the form**ax**. Last updated: May 2nd, 2002.^{2}+ bx + c = 0 (mod n)**Sum of powers:**Table of relations of the form**a**with^{p}+ b^{q}= c^{r}**gcd(a,b,c) = 1**. Last updated: September 7th, 2003.**Ulam's Spiral:**Java applet featuring a graphical view of prime numbers. Last updated on February 14th, 2003.**Factorization using the Elliptic Curve Method:**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. Last updated on February 9th, 2003.**Gaussian Integer Factorization applet:**Finds the factors of complex numbers of the form a+bi where a and b are integers. It also includes a complete calculator with operators and functions using gaussian integers. Last updated on June 1st, 2002.**Gaussian Primes:**Java applet featuring a graphical view of gaussian prime numbers. Last updated on June 15th, 2003.**Discrete logarithm calculator:**Applet that finds the exponent in the expression Base^{Exponent}= Power (mod Modulus). Last updated on March 30th, 2002.**Continued fraction calculator:**This calculator can find the continued fraction expansions of rational numbers and quadratic irrationalities. Last updated on April 28th, 2002.**Every positive integer is a sum of four integer squares:**Constructive proof of this interesting theorem. Last updated: October 5th, 2001.**Sum of squares:**This calculator can find the decomposition of a number or numerical expression in a sum of up to four squares. It does not need its prime factorization. Last updated on November 27th, 2002.**Sum of four cubes:**This calculator can find the decomposition of a number or numerical expression that is not congruent to 4 or 5 (mod 9) in a sum of four cubes. Last updated on March 27th, 2005.**Brilliant numbers:**Interesting problem about products of two primes of the same size.**Factors of Modified Fermat Numbers:**Factors of numbers of the form 4^{3n}+2^{3n}+1 and 4^{3n}-2^{3n}+1.**Factors of numbers near googolplex (10**:^{10^100})**Factors of numbers near googolplexplex (10**:^{googolplex})