Problem A. 700. (May 2017)
A. 700. A positive integer \(\displaystyle n\) satisfies the following: it is possible to select some integers such that if we randomly choose two different integers from this list, say, \(\displaystyle i\) and \(\displaystyle j\), then \(\displaystyle i+j\) \(\displaystyle \mathrm{mod\ } n\) is equal to one of the numbers \(\displaystyle 0,1,\dots,n-1\) with equal probability. Find all numbers \(\displaystyle n\) with this property.
(5 pont)
Deadline expired on June 12, 2017.
Statistics:
7 students sent a solution. 5 points: Baran Zsuzsanna, Gáspár Attila, Matolcsi Dávid, Williams Kada. 4 points: Szabó Kristóf. 0 point: 2 students.
Problems in Mathematics of KöMaL, May 2017