Bernard Frénicle de Bessy

Bernard Frénicle de Bessy (about 1605–1675), was a French mathematician. He was born in Paris. He wrote many papers about mathematics, number theory and combinatorics. The Frénicle standard form, a standard representation of magic squares, is named after him. He solved many problems created by Fermat. He also discovered a taxicab number and in 1693, he described all 880 essentially different normal magic squares of order 4.
Like Fermat, Frénicle was an amateur mathematician, but he wrote letters to famous people such as Descartes, Christiaan Huygens, Mersenne and also Fermat, who was his friend. He is mainly remembered for his discoveries about number theory.