MathDB
A Function to Partition Numbers

Source: 2018 China Team Selection Test 2 Problem 2

January 8, 2018
functionInteger partitionsnumber theorycombinatorics

Problem Statement

An integer partition, is a way of writing n as a sum of positive integers. Two sums that differ only in the order of their summands are considered the same partition. For example, 4 can be partitioned in five distinct ways: 4 3 + 1 2 + 2 2 + 1 + 1 1 + 1 + 1 + 1 The number of partitions of n is given by the partition function p(n)p\left ( n \right ). So p(4)=5p\left ( 4 \right ) = 5 . Determine all the positive integers so that p(n)+p(n+4)=p(n+2)+p(n+3)p\left ( n \right )+p\left ( n+4 \right )=p\left ( n+2 \right )+p\left ( n+3 \right ).