What is the relationship between \(x\) and \(y\) in the table below?

Question

\begin{equation}
\begin{aligned}
&\text { What is the relationship between } x \text { and } y \text { in the table below? }\\
&\begin{array}{|c|c|c|c|c|}
\hline x & 1 & 2 & 3 & 4 \\
\hline y & 1 & 5 & 9 & 13 \\
\hline
\end{array}
\end{aligned}
\end{equation}