In 1949, a conference was held in Los Angles about the newly developed Monte Carlo Method, a computational technique that requires a lot of random numbers. Two Pseudo-Random Number Generators were discussed at this conference; one was the Middle-Square Method, while the other was the Lehmer Generator. Proposed by D. H. Lehmer, this Pseudo-Random Number Generator uses a surpisingly simple formula to produce random numbers.

This generator is also known as the Park-Miller Generator, after Stephen K. Park and Keith W. Miller, who published a paper on the generator in 1988.

Additionally, the Lehmer Generator would become the foundation for the Linear Congruential Generator family.

The formula for this generator is X₁ = aX₀ mod M.

The values for a and M are generally chosen by the person implementing the Pseudo-Random Number Generator. However, for better results, a should be a primitive root of M.