Symbol for permutations in MathJax

In the basic tutorial on MathJax, I'm unable to find the symbol for permutations. Could someone please enlighten me on this ?

• Permutations as in $\frac{n!}{(n-k)!}$? I know of no universally used symbol for those, sometimes $(n)_k$ is used. – Daniel Fischer Jun 6 '15 at 14:42
• If you mean two-line notation, you can use matrices or arrays for that. Copied from Wikipedia: $\sigma=\begin{pmatrix} 1 & 2 & 3 & 4 & 5 \\ 2 & 5 & 4 & 3 & 1\end{pmatrix}.$ See also here and here. (The second link has many formulas, it is better not to open it on slow/mobile devices.) – Martin Sleziak Jun 6 '15 at 14:48
• So I guess shall have to use $_n$P$_k$ or P(n,k) – true blue anil Jun 6 '15 at 20:18
• @Fischer: I see, unlike a special symbol for combinations, none universal for permutations exist. Thanks. – true blue anil Jun 7 '15 at 6:30