For $x^2+x+1$, there exist infinitely many integers $w$ such that $x^2+x+1+w$ defines the same field as $x^2+x+1$.
They are $w$ $=$ $6, 60, 546, 4920,...$ There is a closed form for odd $k$, namely $w$ $=$ $((3^k+1)/4)$$-1$
I can't seem to prove / disprove this for the fact of weather there are infinitely many integers $w$ such that $x^4+x^3+x^2+x+1+w$ defines the same field as $x^4+x^3+x^2+x+1$.
The same with weather there are infinitely many integers defining $w$ in $x^6+x^5+x^4+x^3+x^2+x+1+w$ defines the same field as $x^6+x^5+x^4+x^3+x^2+x+1$.
If there is at least one integer $w$ for degrees $4$ or $6$, please post them as a counterexample.