You can add "negative space" with \!. Try this:
which givesCode:\iiiint\!\!\!\int dx\,dy\,dz\,dt\,du
$\displaystyle \iiiint\!\!\!\int dx\,dy\,dz\,dt\,du$
Also, note the use of the \, spacer. I don't think I have ever seen you use it, but it will make your integrals a bit nicer by putting space between the integrand and the variable of integration. e.g.
Instead of $\displaystyle \int xdx$, you'd get $\displaystyle \int x\,dx$.
Actually, I believe he was trying to express a counterclockwise contour integral (look closely and notice the arrow).
I found this really old post on comp.text.tex by Donald Arseneau that provides a method to get it to look right, but I do not think these forums have the right packages.
Hmm..I still do not see an arrow indicating direction.
$\displaystyle
\def\Xint#1{\mathchoice
{\XXint\displaystyle\textstyle{#1}}%
{\XXint\textstyle\scriptstyle{#1}}%
{\XXint\scriptstyle\scriptscriptstyle{#1}}%
{\XXint\scriptscriptstyle\scriptscriptstyle{#1}}%
\!\int}
\def\XXint#1#2#3{{\setbox0=\hbox{$#1{#2#3}{\int}$}
\vcenter{\hbox{$#2#3$}}\kern-.5\wd0}}
\def\dashint{\Xint-}
\def\ddashint{\Xint=}
\def\clockint{\Xint\circlearrowright}
\def\counterint{\Xint\rotcirclearrowleft}
\def\rotcirclearrowleft{\mathpalette{\RotSymbol{-30}}\circlearrowleft}
\def\RotSymbol#1#2#3{\rotatebox[origin=c]{#1}{$#2#3$}}$
Note the part in red. The intention was for a counterclockwise line integral...Code:\mathop{\int\mkern-20.8mu \circlearrowleft}\nolimits_C {{\mathbf{F}} \cdot d{\mathbf{r}}} = \iint\limits_R {{\text{curl}} \,{\mathbf{F}} \cdot {\mathbf{k}}\,dA}
You probably don't see the arrow because the arrow is at the top of the circle: $\displaystyle \circlearrowleft$
...The integral sign blocks it...