Paul Leyland

Paul Leyland is a number theorist who has studied integer factorization and primality testing.

He has contributed to the factorization of RSA-129, RSA-140, and RSA-155, as well as potential factorial primes as large as 400! + 1. He has also studied Cunningham numbers, Cullen numbers, Woodall numbers, etc., and numbers of the form $x y + y x$ , which are now called Leyland numbers. He has been involved with the NFSNet project.

In 2002 he coauthored a paper with Samuel S. Wagstaff Jr. entitled "MPQS with three large primes" in the Proceedings of the Algorithmic Number Theory Symposium 2002. Since Wagstaff coauthored a paper with Paul Erdős, this means Leyland has an Erdős number of 2.