The following example redefines \@arabic
to change the behaviour of \arabic
. If the number is 13 or larger, the increased number is printed instead:
1, 2, ... 11, 12, 14, 15, ...
The oddness test of \cleardoublepage
is based on the counter value, that is not changed
by the redefined \@arabic
.
Example file:
\documentclass{book}
\makeatletter
\renewcommand*{\@arabic}[1]{%
\ifnum#1<13
\the\numexpr(#1)\relax
\else
\the\numexpr(#1)+1\relax
\fi
}
\makeatother
\begin{document}
\chapter{First chapter}
\addtocounter{chapter}{10}
\newpage\null
\newpage\null
\newpage\null
\newpage\null
\newpage\null
\newpage\null
\newpage\null
\newpage\null
\newpage\null
\chapter{Chapter before 13}
\chapter{Chapter after 13}
\end{document}
An alternative is using 12a
instead of 13
to avoid messing up the oddness too much:
\makeatletter
\renewcommand*{\@arabic}[1]{%
\ifnum#1=13 %
12a%
\else
\the\numexpr(#1)\relax
\fi
}
\makeatother
triskaidephobia
tag, that unfortunately might not survive automatic purges of single-use tags.