\documentclass[12pt]{article}
\usepackage{array}

\newcolumntype{S}{>{\scancell}l<{\endscan}}
\def\scancell#1\ignorespaces#2\unskip\endscan{%
  $\mathsf{#2}$%
}

\begin{document}

\begin{tabular}{S|l}
\texttt{mathsf} & normal\\\hline
1234567^4_3 & $123456^4_3$\\
\end{tabular}

\end{document}
