\documentclass{article}
\usepackage[xindy]{imakeidx}
\usepackage{hyperref}
\makeindex
\begin{document}

\begin{table}
a table
  \caption{hello}\label{t1}
\end{table}

See Table \ref{t1}.
\index{y formula}
\begin{equation} 
y(n) = \langle x\rangle. % \qquad\hbox{($x$ real)}
\label{eq1}
\end{equation}
\index{\'ecole}
\begin{equation} 
y_2(n) = \langle x_2\rangle. % \qquad\hbox{($x$ real)}
\label{eq2}
\end{equation} 
See eq.~\ref{eq1} and eq.~\ref{eq2}.
\index{accent}
\index{aça}
\index{aea}
\index{aaa}
\index{\c{c}\`a}
\index{\c{C}a}


\printindex
\end{document}
