Welcome to the forum!
In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.
Welcome to the forum Denya;
Hope you enjoy your stay here....
"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay
Hi Denya,Welcome to the forum.hope you will like it here.