MathDB
f(n) is a perfect square for all n

Source: Benelux 2009

January 29, 2011
functionnumber theory proposednumber theory

Problem Statement

Find all functions f:Z>0Z>0f:\mathbb{Z}_{>0}\rightarrow\mathbb{Z}_{>0} that satisfy the following two conditions:  f(n)\bullet\ f(n) is a perfect square for all nZ>0n\in\mathbb{Z}_{>0}  f(m+n)=f(m)+f(n)+2mn\bullet\ f(m+n)=f(m)+f(n)+2mn for all m,nZ>0m,n\in\mathbb{Z}_{>0}.