\documentclass{article}
\begin{document}
\begin{tabular}{ll|l}
? & $\mathaccent'27{u}_s$\\
$\acute{a}$ & $\mathaccent"7013{a}$ & $\acute{abc}$\\
$\bar{a}$   & $\mathaccent"7016{a}$ & $\bar{abc}$\\
$\breve{a}$ & $\mathaccent"7015{a}$ & $\breve{abc}$\\
$\check{a}$ & $\mathaccent"7014{a}$ & $\check{abc}$\\
$\ddot{a}$  & $\mathaccent"707F{a}$ & $\ddot{abc}$\\
$\dot{a}$   & $\mathaccent"705F{a}$ & $\dot{abc}$\\
$\grave{a}$ & $\mathaccent"7012{a}$ & $\grave{abc}$\\
$\hat{a}$   & $\mathaccent"705E{a}$ & $\hat{abc}$\\
$\tilde{a}$ & $\mathaccent"707E{a}$ & $\tilde{abc}$\\
$\vec{a}$   & $\mathaccent"017E{a}$ & $\vec{abc}$\\
            & $\mathaccent"7017{a}$ \\
$\widetilde{aaa}$   & $\mathaccent"0365{aaa}$ \\
$\widehat{aaa}$     & $\mathaccent"0362{aaa}$ \\
\end{tabular}
\end{document}