Plimpton 322

Plimpton 322 is a Babylonian clay tablet, notable as containing an example of Babylonian mathematics. It has number 322 in the G.A. Plimpton Collection at Columbia University. This tablet, believed to have been written about 1800 BC, has a table of four columns and 15 rows of numbers in the cuneiform script of the period.

This table lists what are now called Pythagorean triples, i.e., integers a, b, c satisfying . The triples are too many to have been constructed by brute force. From a modern perspective, a method for constructing such triples is a significant early achievement, known before only among the Greeks. At the same time, one should recall the tablet's author was a scribe, rather than a professional mathematician; it has been suggested that one of his goals may have been to produce examples for school problems.

Although the tablet was interpreted in the past as a trigonometric table, more recently published work sees this as anachronistic, and gives it a different function. For readable popular treatments of this tablet see Robson (2002) or, more briefly, Conway & Guy (1996). Robson (2001) is a more detailed and technical discussion of the interpretation of the tablet's numbers, with an extensive bibliography.