pandoc cannot convert latex formula containing "*{20}{l}"

[xlf826796931]

I want to convert the following latex formula to a docx document:
$\left\{ {\begin{array}{*{20}{l}} {(m + 2)x = 1}\\ {3x - (m - 3){y^{\left| m \right| - 2}} + 4 = 0} \end{array}} \right.$

However, I received the following error message. Use pandoc-try to restore the problem.

Could not convert TeX math \left\{ {\begin{array}{*{20}{l}} {(m + 2)x = 1}\\ {3x - (m - 3){y^{\left| m \right| - 2}} + 4 = 0} \end{array}} \right., rendering as TeX: t\{ {\begin{array}{*{20}{l}} {(m + 2)x = ^ unexpected "*" expecting white space, letter, "|" or "}"

I noticed that pandoc can't seem to convert latex containing *{20}{l}

how to solve this problem？

[jgm]

Today I learned that

{*{20}{l}}

means:

*{num}{cols}
Equivalent to num copies of cols

We should support that -- I will move this issue to jgm/texmath where the change would have to be made.