The photoelectric number
sieve, ca. 1933.
10.0 x 8.0 inches

Dick Lehmer was a leading authority on number and computation theory,
and he made signal contributions in the field of mechanical (later computer)
applications to mathematical problems. With his father’s help and encouragement,
he constructed a mechanical sieve capable of factoring very large numbers,
which was displayed to the public at the World’s Fair in Chicago in 1933.
He later helped develop and test ENIAC (Electronic Numerical Integrator
and Calculator), the first modern digital computer.
During the loyalty oath controversy in the early 1950s, Lehmer briefly
left Berkeley to serve as Director of the National Bureau of Standards’
Institute for Numerical Analysis. 
“An Account of the Proposed
Machine,” corrected typescript,
6 l. , ca. 1930
8.5 x 11.0 inches 
At left is presumably a draft of the successful proposal to the Carnegie
Institution for funding to construct the Lehmers’ first electric factoring
machine, a signal achievement in both number theory and computer science.
“…To perform
the operation with pencil and paper one must start with the million or
so numbers among which the solution is known to lie. Actually to
write out all these numbers is obviously impossible … We therefore propose
to construct a machine which will canvass a million numbers in about three
minutes ….”

“Notes on the Lehmer’s
contributions to FLT,” autograph manuscript
9 l., n.d.
8.5 x 11.0 inches 
This manuscript in Dick Lehmer’s hand reminisces about
Vandiver's work on Fermat's Last Theorem, “the bestknown of all Diophantine
problems” that remained unsolved for 350 years, until 1993. Here
Lehmer also demonstrates, once again, the importance of his collaboration
with Emma. Together they computed many Bernoulli numbers for Vandiver. 
Guide to Tables in the
Theory of Numbers
Washington, D. C.: National
Research Council, National Academy of Sciences, 1941
7.0 x 10.0 inches 
The Guide to Tables in the Theory of Numbers is Lehmer's best
known monograph, and demonstrates the close link with his father's career. 