How to write the limits under all three summation : $\sum \sum \sum_{0 \leq i < j

Question

I want to write the limits under all three summation means starting from summation left side going towards right side ( dependent limits) , Please help on this.

$$\sum \sum \sum_{0 \leq i < j <k \leq n } 1 }$$

thanks..

Answer 1

You can define you own math operator, MySum as defined below, or use \mathop and \limits:

Code:

\documentclass{article}
\usepackage{amsmath}
\DeclareMathOperator*{\MySum}{\sum \sum \sum}
\begin{document}
\noindent
Using \verb|\MySum|
[
    \MySum_{0 \leq i < j}
]
or use \verb|\mathop|
[
    \mathop{\sum \sum \sum}\limits_{0 \leq i < j}
]
\end{document}