Permutations and Combinations in chess

Nicksypilicksy #1
I am investigating permutations and combinations of the knight. Given that there are no other pieces on the board, and that the knight can make 2 moves, we can observe that there are 18 possibilities. Would this be permutations or combinations? and, what would be n and r? Also, if repetitions were not allowed, there would be 13 possibilities, how is this shown mathematically (i guess it is with the npr/x!)

i.stack.imgur.com/CWHpL.png
//this is the image of the mathematical problem

Why?

math.stackexchange.com/questions/2653590/permutations-and-combinations-in-chess

There is another Knight puzzle thing you might like...Its called the "Knight's Tour" The knight has to cover all the squares of the board in successive moves. There are numerous solutions. I think this is a permutation. :]

That's a Graph Theory problem (covering all the squares)

The famous Knight's Tour has numerous solutions.
It was a popular "exhibition" of the legendary Turk , the chess automaton...
Who said that Stockfish didn't exist in the 18th century?? 😇

I think that the only thing you will get out of completing a knight's tour...is a very good understanding of how the knight moves. Its an "L" shape ...right? :]

A knight can go to the nearest squares which are not in the same diagonal, same line or same file with it. (FIDE rules)