My father was a Berkely math professor interested in number theory and computation, and I became interested as well, being fascinated by discussions with my dad on his publication of a "Factor table for the first ten million numbers" when I was four and a "List of prime numbers from 1 to 10006721" when I was nine.
After getting degrees from Berkeley, University of Chicago, and Brown University, I served as mathematics professor at Berkeley for 32 years.
In the McCarthy years in the 1950s, I refused to sign the necessary oath, was deemed a Communist sympathiser, and lost my Berkeley position until the courts eventually declared the oath requirement to be unconstitutional.
In addition to receiving numerous awards, I published almost 200 research papers, especially relative to the growing use of mechanical and electronic sieve computers.
My common tendency was to try to use computers to prove number theoretic conjectures wrong; if that did not work, I tried to reduce the number of cases under investigation or reveal the need for additional assumptions.
To be more specific, I investigated the Lucas-Lehmer primality test which uses the Fermat congruence, tested whether a Mersenne number was prime, contributed to knowledge about the density of primes with a given primitive root, studied the partition function, verified some of Ramanujan's conjectures, and was the first to use a computer to attack the Riemann Hypothesis by checking if the roots lay on the critical line.
Derrick Henry Lehmer (1905-1991)