Mathematician:Maurice Kraitchik

Belgian mathematician and writer who wrote on number theory and recreational mathematics.

Proved in 1922 that the Mersenne number $M_{257}$ is composite, contrary to the claims of Marin Mersenne.

Nationality
Belgian

History

 * Born: April 21, 1882, Minsk, Russian Empire (now Belarus)
 * 1910: Graduated from the University of Liège
 * 1923: Graduated from the Université Libre de Bruxelles
 * 1931 - 1939: Editor of
 * Between 1939 and 1945: Emigrated to the United States, started teaching at the New School for Social Research in New York City
 * Died: August 19, 1957, Brussels, Belgium

Achievements

 * 1922: Proved that the Mersenne number $M_{257}$ is composite.
 * 1953: Inspired the Two Envelopes Problem.

Books, Publications, etc.

 * 1922: Théorie des Nombres
 * 1924: Recherches sur la Théorie des Nombres
 * 1930: La Mathématique des Jeux ou Récréations Mathématiques
 * 1942:
 * 1944: Alignment Charts