Chapter 4: Systems Based on Numbers

Section 4: The Sequence of Primes

Trapezoidal primes

If one lays out n objects in an a × b rectangular array, then n is prime if either a or b must be 1. Following the Pythagorean idea of figurate numbers one can instead consider laying out objects in an array of b rows, containing successively a, a-1, ... objects. It turns out all numbers except powers of 2 can be represented this way.

From Stephen Wolfram: A New Kind of Science [citation]