Answer
The Proposed Negation is incorrect
Correct Negation: There exists an integer $n$ such that $n^2$ is even and $n$ is not even.
Work Step by Step
Negation of the statements of the form, "For all x, q", q being a statement, is "There exists x, ~q".
In this case,
q : $n$ is even
So, ~q: $n$ is not even.