On a property of the polynomials $x^n+(1-x{)}^n+a^n$

The polynomials $x^n+(1-x{)}^n+a^n$ arise naturally from FLT (Fermat’s Last Theorem). We formulate a conjecture about them which is a generalization of FLT. We investigate the complex roots of these polynomials, and our main result is that in the cases $\mathrm{\mid }a\mathrm{\mid }\le \frac{1}{2}$ and $a=-1$, they lie on an explicitly given curve while ‘filling in’ that curve. We hypothesize that this property can be generalized to hold for other $a$ as well.