MathDB

Let

n

be a positive integer. Chef Kao has

n

different flavors of ice cream. He wants to serve one small cup and one large cup for each flavor. He arranges the

2n

ice cream cups into two rows of

n

cups on a tray. He wants the tray to be colorful, so he arranges the ice cream cups with the following conditions:
[*]each row contains all ice cream flavors, and [*]each column has different sizes of ice cream cup. Determine the number of ways that Chef Kao can arrange cups of ice cream with the above conditions.

Problem Statement