Cecil C. Rousseau

Cecil Clyde Rousseau (born January 13, 1938 in Philadelphia) is a mathematician and author who specializes in graph theory and combinatorics. He is a professor emeritus at The University of Memphis and former chair of the USAMO.
Rousseau received his Ph.D. in 1968 from Texas A&M University.
He has an Erdős number of 1, and is Erdős' 5th most common co-author, with 35 joint papers.
In 2012, Rousseau received the Paul Erdős Award from the World Federation of National Mathematics Competitions.
To his students and colleagues, he's known affectionately as C²R.