# Mathematician:Fortuné Landry

## Mathematician

French mathematician mainly working in the field of factorization of large integers.

Between $1867$ and $1869$, he published factorizations of all the numbers of the form $2^n \pm 1$ for $n \le 64$.

At this time, held the record for the largest known prime: $3 \, 203 \, 431 \, 780 \, 337 = \dfrac {2^{59} - 1} {179 \, 951}$.

In $1880$, published the factorization of the Fermat number $F_6 = 2^{64} + 1 = 274 \, 177 \times 67 \ 280 \, 421 \, 310 \, 421 \, 310 \, 721$, which he obtained after the work of a few months.

According to Édouard Lucas, he subsequently demonstrated the primacy of that second factor, which holds the record for the largest non-Mersenne prime found without a computer.

French

## History

• Born: 13 April 1799 in Paris, France
• Died: 30 January 1895 in 16e arrondissement de Paris, France

## Publications

• 1859: Procédés nouveaux pour démontrer que le nombre $2 \, 147 \, 483 \, 647$ est premier: septième mémoire sur la théorie des nombres
• 1867: Aux mathématiciens de toutes les parties du monde. Communication sur la décomposition des nombres en leurs facteurs simples
• 1869: Décompositions des nombres $2^n \pm 1$ en leurs facteurs premiers de $n = 1$ à $n = 64$ (moins quatre)
• 1880: Note sur la décomposition du nombre $2^{64} + 1$ (Extrait) (C.R. Acad. Sci. Vol. 91: 138)

## Also known as

His first name Fortuné often appears as Fortune.