Faulhaber's triangle, the Bernoulli numbers and what they're good for.
Abstract: Johannes Faulhaber's name is now almost forgotten, but in his day (1580-1635) he was known as the great arithmetician of Ulm and both Rene Descartes and Johannes Kepler went to Ulm to learn his secrets. Descartes intended to stay a week but in fact stayed a month. Faulhaber prediscovered the Bernoulli numbers and their relationship to power sums.
(Tea served in First Floor Commons Room at 3:30pm.)