Prime Number Spiral - 8.01

The Prime Number Spiral (a.k.a. the Ulam Spiral) is constructed as follows:

Consider a rectangular grid. We start with the central point and arrange the positive integers in a spiral fashion (anticlockwise). The prime numbers are then marked. There is a tendency for the prime numbers to occur on diagonal lines, however far out into the spiral one goes. This is software is for exploring the Prime Number Spiral.

It also

• allows coloring of the prime numbers in various ways,
• displays a random arrangement to compare with the primes and
• shows how square and triangular numbers are located on the spiral.