MathDB
P 14

Source:

May 25, 2007
Additive Number Theory

Problem Statement

Let nn be a non-negative integer. Find all non-negative integers aa, bb, cc, dd such that a2+b2+c2+d2=7ā‹…4n.a^{2}+b^{2}+c^{2}+d^{2}= 7 \cdot 4^{n}.