Here is one answer from Heureka
https://web2.0calc.com/questions/another-triangle-problem-with-no-explanation-last-time-i-asked#r2
Here is a different answer from me.
https://web2.0calc.com/questions/quick-question_43
I think the answers are different.
You will have to decide which one, if either, is correct.
Correction: I think at least one of the questions is a slightly different question from the one you asked.
Still they are very similar and at a glance it appears we have tackled them very differently from each other.
I’ll interpret your question as follows. You have an n×n grid of n2 cells. You’ve got one color. Each square can be either colored or left uncolored. (I’ll use 0 for uncolored and 1 for colored.) How many ways can the cells be colored so that no two rows have the same number of colored cells and no two columns have the same number of colored cells. www.mywawavisit.com