Another notation question: What is $\genfrac{\{}{\}}{0}{}{n}{n-1}$?

Question

Hi I'm sorry to ask another question so soon but I'm unaware of what the following notation means. Again this is taken from a Combinatorics context.

It looks like this: $\begin{Bmatrix} n\\ n-1 \end{Bmatrix}$

I'm told it is equal to $n\choose 2$

EDIT: The question in hand: Find a number $n>2$ such that n and $\begin{Bmatrix} n\\ n-1 \end{Bmatrix}$ have different parity.

Thanks for any help.

Answer 1

It may be the Stirling number of the second kind.

Answer 2

These are Stirling numbers of the second kind and here is a reference to your relation:

$$\begin{Bmatrix} n\\ n-1 \end{Bmatrix} = {n \choose 2}$$