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Determine all positive integers n

Source: 7th European Mathematical Cup , Senior Category , Q1

December 25, 2018
number theoryalgebra

Problem Statement

A partition of a positive integer is even if all its elements are even numbers. Similarly, a partition is odd if all its elements are odd. Determine all positive integers nn such that the number of even partitions of nn is equal to the number of odd partitions of nn. Remark: A partition of a positive integer nn is a non-decreasing sequence of positive integers whose sum of elements equals nn. For example, (2;3;4),(1;2;2;2;2)(2; 3; 4), (1; 2; 2; 2; 2) and (9)(9) are partitions of 9.9.