\begin{definition}[Definition:Apéry's Constant]
'''Apéry's constant''' is the value of the infinite sum:
:$\map \zeta 3 = \ds \sum_{n \mathop = 1}^\infty \frac 1 {n^3}$
where $\zeta$ denotes the Riemann zeta function.
Its approximate value is given by:
:$\map \zeta 3 \approx 1 \cdotp 20205 \, 69031 \, 59594 \, 28539 \, 97381 \, 61511 \, 44999 \, 07649 \, 86292 \ldots$
{{OEIS|A002117}}
\end{definition}