Josephus problem

Named after Flavius Josephus, a Jewish historian of the 1st century, who describes such a situation in his account of the siege of Yodfat.

the Josephus problem

1. (mathematics) A theoretical problem in which every nth person, counting around a circle of people, is chosen for execution, and this process repeats after the removal of each chosen person, with the last person left being freed. The problem is to select one's position so as to be the last to be chosen.