Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
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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.


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