Solution:
We have x2z2=2013(x2+xyz+z2). Let d=gcd(x,z) and x=da,z=db. Then a2b2d2=2013(a2+aby+b2).
As gcd(a,b)=1, we also have gcd(a2,a2+aby+b2)=1 and gcd(b2,a2+aby+b2)=1. Therefore a2∣2013 and b2∣2013. But 2013=3⋅11⋅61 is squarefree and therefore a=1=b.
Now we have x=z=d and d2=2013(y+2). Once again as 2013 is squarefree, we must have y+2=2013n2 where n is a positive integer.
Hence (x,y,z)=(2013n,2013n2−2,2013n) where n is a positive integer.