An integer $n$ is called $k$-special, with $k$ a positive integer, if it's the sum of the squares of $k$ consecutive integers. For example, $13$ is $2$-special, since $13=2^2+3^2$, and $2$ is $3$-special, since $2=(-1)^2+0^2+1^2$. a) Prove that there's no perfect square that is $4$-special. b) Find a perfect square that is $I^2$-special, for some odd positive integer $I$ with $I\ge 3$.