\begin{tikzpicture}[
	cavity/.style = {
		matrix of nodes,
		nodes in empty cells,
		column sep = -\pgflinewidth,
		row sep    = -\pgflinewidth,
		nodes={
			inner sep=0mm,
			outer sep=0pt,
			minimum size=5mm,
			text height=\ht\strutbox,
			text depth=\dp\strutbox,
			draw
		}
	}
]

\matrix[cavity,label=below:{\(N=15\)}] {
	5 & 4 & 4 & 4 & 5 \\
	3 & 3 & 2 & 3 & 4 \\
	2 & 2 & 2 & 2 & 3 \\
	1 & 1 & 1 & 1 & 1 \\
	0 & 1 & 1 & 1 & 0 \\
};

\matrix[cavity,label=below:{\(N=30\)}] at (3, 0) {
	4 & 3 & 3 & 3 & 4 \\
	1 & 1 & 1 & 1 & 2 \\
	1 & 0 & 0 & 1 & 2 \\
	0 & 0 & 0 & 1 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
};

\matrix[cavity,label=below:{\(N=60\)}] at (6, 0) {
	3 & 2 & 2 & 2 & 3 \\
	0 & 0 & 0 & 0 & 1 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
};

\matrix[cavity,label=below:{\(N=120\)}] at (9, 0) {
	2 & 1 & 1 & 1 & 2 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
};

\matrix[cavity,label=below:{\(N=240\)}] at (12, 0) {
	1 & 0 & 0 & 0 & 1 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & 0 & 0 & 0 \\
};
\end{tikzpicture}