Ferrers function

Okay kiddo, let me explain what Ferrers function is.

So imagine we have a big rectangle with some dots inside. Now, we want to count how many dots are in each row and write them down in a list. This list is called the Ferrers function.

But wait, there's a special rule! We can't have more dots in a row than the row number itself. So if it's the first row, we can only have one dot. If it's the second row, we can have at most two dots in that row.

Let me show you an example. Suppose we have this rectangle, with 11 dots inside:

. . . . .
. . .
. . . . .
. . . .
.

So the first row has one dot, the second row has two dots, the third row has three dots, the fourth row has three dots, and the fifth row has two dots. So the Ferrers function for this rectangle would be:

1, 2, 3, 3, 2

And that's what the Ferrers function is all about! We count the number of dots in each row of a rectangle, with the limitation that we can't have more dots in a row than the row number itself.