zak seidov wrote:
>
> All terms are even?
> Equation 2^n + 3^n = x^2 has no solution (with integer
> x and n)?
>
That's correct. For n>=2, 2^n+3^n falls into a pattern
of quadratic non-residues, taken modulo 20:
13, 15, 17, 15, 13, 15, 17, 15, ...