How was F 6 Factored?
H. C. Williams · Mathematics of Computation · 1993
In 1880 at the age of 82 Fortune Landry factored the 20 digit number F6 = 264 + 1. How did he do it? Landry himself never described how he factored F6; however, he did leave enough clues in his work and letters to provide some indication of the ideas with which he was working. In this paper we present a likely reconstruction of Landry's technique.