 as the power series <span class="inlinemediaobject"><img src="../../../equations/special_functions_blurb1.svg"></span>,
        with <span class="emphasis"><em><code class="literal">n! = 1x2x3x4x5...xn</code></em></span> (and <span class="emphasis"><em><code class="literal">0!
        = 1</code></em></span> by definition) being the factorial of <span class="emphasis"><em><code class="literal">n</code></em></span>.
        In particular, the exponential function is well defined for real numbers,
        com