MathDB

Call One Another

Source: 2000 National High School Mathematics League, Exam Two, Problem 3

March 11, 2020

Problem Statement

There are

n

people, any two of them have called each other at most once. In any group of

n-2

of them, anyone of the group has called with other people in this group for

3^k

times, where

k

is a non-negative integer (the value of

k

is fixed). Find all possible integers

n