A replacement to "\mathbbm{1}" with type-1 fonts
The doublestroke package provides blackboard fonts in type 1 format, including the \mathds{1}
that you are looking for.
It does not exactly look like those of bbm
, but could likely be used as a drop in replacement in your case
Another possibilty is use the package bbold
symbol font to get a similar \mathds{1}
.
\documentclass{article}
\usepackage{bbold}
\usepackage{mathtools}
\begin{document}
$\mathbb{1}$
\end{document}
Using dsfont
you will have:
\documentclass{article}
\usepackage{dsfont}
\begin{document}
$\mathds{1}$
\end{document}