Fortune Landry

Fortuné Landry ( April 13, 1799 - January 30, 1895 ) was a French mathematician .

In 1867 he found the largest prime number to date . It was the divisor of the Mersenne number 2 to the power of 59 - 1 , which results from dividing it by 179,951:

(2 ⁵⁹ - 1) / 179,951 = 3,203,431,780,337

Between 1867 and 1869 Landry published numerous articles on the prime factorization of the first 64 Mersenne numbers and some Fermat numbers . ${\displaystyle M_{n}}$ ${\displaystyle {\mathfrak {F}}_{n}}$

At the age of 82, Landry is said to have factored the seventh Fermat number (a 20-digit number). He used a method that was later reconstructed and published by Hugh C. Williams . Landry did not publish his method, but evidence was found in his estate. ${\displaystyle F_{6}=2^{2^{6}}+1,}$

literature

• Fortuné Landry: Théorème de Fermat: recherches nouvelles. Volume 1, 1755.
• Fortuné Landry: Théorème sur les réduites d'une nouvelle espèce de fractions continues. L. Hachette, 1856.

Individual evidence

1. ^ Archives de Paris , fichier de l'état-civil reconstitué.
2. ↑ Archives de Paris , état-civil numérisé du 16e arrondissement, acte de décès N ^o 138 de l'année 1895. "Ancien professeur", il décède à 95 ans à son domicile 174 rue de la Pompe .
3. ^ David Wells: Prime Numbers. The Most Mysterious Figures in Math ( Memento December 3, 2013 in the Internet Archive ). Wiley, Hoboken, N. J. 2005, ISBN 0-471-46234-9 , p. 15.
4. ^ Hugh C. Williams: How was F6 Factored? In: Mathematics of Computation . Volume 61, 1993, p. 463.