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\begin{document}
\begin{tabular}{l|rrrrrrr}
 &  $A_{3}$ & $A_{4}$ & $A_{5}$ & $A_{6s}$ & $A_{7}$ & $A_{8}$ & $A_{9}$ \\
\hline
$A_{3}$ & $1.00 $ &         $-0.18 $ &      $-0.20$ &       $-0.06 $ &      $-0.01 $ &      $0.04 $ &       $-0.03 $  \\
$A_{4}$ &  &       $1.00 $ &        $0.28 $ &       $-0.10$ &       $-0.02 $ &      $0.01 $ &       $0.07 $  \\
$A_{5}$ &  &  &       $1.00$ &        $-0.15 $ &      $-0.05 $ &      $0.00$ &       $0.04 $  \\
$A_{6s}$ &  &  &   &   $1.00 $ &        $-0.01 $ &      $-0.01 $ &      $0.03 $  \\
$A_{7}$ &  &  &  &  &   $1.00 $ &        $0.21 $ &       $-0.19 $  \\
$A_{8}$ &  &  &  &  &   &  $1.00 $ & $-0.03 $  \\
$A_{9}$ &  &  &  &  &  &  & $1.00$  \\
\end{tabular}
\end{document}
