How to use more than 10 tab stops in bmatrix or other amsmath matrix environments?

Googling "10 columns" together with "tex" and "halign" lead me to this document, where it is explained that, e.g.,

\setcounter{MaxMatrixCols}{20}

enables you to use 20 columns.

Yet another method is to use the array construct from amsmath package.

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\begin{equation}
\left[ \begin{array}{@{}*{11}{c}@{}}
     1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & 11\\
\end{array} \right]
\end{equation}

\end{document}