[Tex/LaTex] Right curly brace at the end of an equation

equations

I'm trying to write this equation:
enter image description here

I'm facing problem with the curly brace.

I tried using \right

\begin{equation}
2 \uparrow \uparrow k \stackrel{\text{def}} = \left.2^{2^{2^{.^{.^{.^{{2}}}}}}}\right\}
\end{equation}

enter image description here

which isn't what we want.

and the same result using \bigg :

\begin{equation}
2 \uparrow \uparrow k \stackrel{\text{def}}= 2^{2^{2^{.^{.^{.^{{2}}}}}}}\bigg\}.
\end{equation}

Thanks in advance.

Best Answer

One way to achieve right curly braces is:

\documentclass{article}
\usepackage{array}

\begin{document}
\[
\left.\begin{array}{c}
2\uparrow\uparrow k = 2^{2^{2^{2^2}}}
  \end{array}\right\}
\]
\end{document}

enter image description here