%% 
%%  Ein Beispiel der DANTE-Edition
%%  Mathematiksatz mit LaTeX
%%  3. Auflage
%%  Beispiel 08-03-4 auf Seite 167.
%%  Copyright (C) 2018 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% ==== 
% Show page(s) 1
%% 
%% 
\documentclass[10pt]{screxa}
\pagestyle{empty}
\setlength\textwidth{122.40707pt}
\AtBeginDocument{\setlength\parindent{0pt}}
%StartShownPreambleCommands

%StopShownPreambleCommands
\begin{document}
$a\atopwithdelims() b$       \medskip

${n \atopwithdelims() k} = {n!\above1pt k!(n-k)!}$
\medskip

$\displaystyle{a\atopwithdelims\{. b}$
\end{document}