Number Theory
Handy JavaScript based Number Theory crunchers. For help with JavaScript and other Web related technology, please visit Usisu.

Ulam Numbers

The first Ulam number(s)

Factorial

!

Geometric Series


Sigma * j
j=0

Fibonacci Numbers

The first Fibonacci number(s)

Lucas Numbers

The first Lucas number(s)

Binomial Coefficients

choose

Binomial Theorem

Expand (x + y)n, where n = using the

Divisibility

Does divide

Division Algorithm

Let a= & b= such that a=b*q+r for the following q & r

Base Conversion

Convert to base (answer is backwards).

Prime

Is prime

gcd(x,y)

gcd(, )

Towars of Hanoi

We've got 3 pegs, A, B, and C... How many disk(s) would you like to use?

The Amazing Number Finder

Think of a multi-digit number x, where x is an element of Z+. Lets let ai represent the ith digit (left to right) of a number a. Calculate y = x0 + x1 + ... + xn, and then, z = x - y. Now, mentally remove any single zi, except for 0's and 9's, and give me the rest of the digits (in order please): . Okay, The Amazing Number Finder is ready to . The number you omitted was .
(the cool thing is that this algorithm finds how far away your number is to the next multiple 9 in a very optimized manner).

© 1996-2004 Kristian Hammer