Derrick Norman Lehmer

Derrick Norman Lehmer (27 July 1867, Somerset, Indiana, USA — 8 September 1938 in Berkeley, California, USA) was an American mathematician and number theorist. He was educated at the University of Nebraska, obtaining a bachelor's degree in 1893 and master's in 1896. Lehmer was awarded his Ph.D. from the University of Chicago in 1900 for a thesis Asymptotic Evaluation of Certain Totient-Sums under the supervision of E. H. Moore. He was appointed instructor in mathematics at the University of California at Berkeley in 1900 and married Clara Eunice Mitchell on 12 July 1900 in Decatur, Illinois. He was promoted to professor at Berkeley in 1918 and continued to teach there until retiring in 1937. In 1903, he presented a factorization of...