To get an expression, exp, to appear as a superscript, you just type ^{exp}.
Can be used only in math mode. Thus, for a simple expression that is part of the running text:
x$^3$ is the third power of x
should display as "x3 is the third power of x". Note that
the braces around the argument may be omitted if the superscript is
a single character.
If a symbol has both subscripts and superscripts, the order doesn't matter.
The following are equivalent:
a_n^2 and a^2_n
Superscripts may have their own superscripts:
$x^{y^{z}}$
should display something like
z
y
x