Edouard Lucas

Édouard Lucas was a French mathematician, born in Amiens in 1842 and died in Paris in 1891, best known for his results in number theory. He was educated at the École Normale in Amiens, worked at the Paris Observatory under Le Verrier, served as an artillery officer in the Franco-Prussian War, and later taught mathematics at the Lycée Saint Louis and the Lycée Charlemagne in Paris. He studied the Fibonacci sequence, gave the closed formula for its terms, and the associated Lucas sequences carry his name. For computing his lasting contribution is a set of primality-testing methods essentially those used today. In 1876 he used them to prove that the Mersenne number two to the power 127 minus one is prime, still the largest prime found without a computer. His test for Mersenne primes was refined by Derrick Henry Lehmer in 1930 and is known as the Lucas-Lehmer test.