(In reply to
Solution by xdog)
If non-zero squares aren't disallowed, then that is a perfectly good solution.
However, here is the definition given on www.mathworld.wolfram.com which lists "1" as the first square number:
A square number is a figurate number of the form <IMG class=inlineformula height=16 alt=S_n==n^2 src="http://mathworld.wolfram.com/images/equations/SquareNumber/inline1.gif" width=45 border=0>, where <IMG class=inlineformula height=15 alt=n src="http://mathworld.wolfram.com/images/equations/SquareNumber/inline2.gif" width=7 border=0> is an integer. A square number is also called a perfect square. The first few square numbers are 1, 4, 9, 16, 25, 36, 49, ... (Sloane's A000290).
Sloane's A00290, interestingly enough, includes "0" as the start of the sequence.