Talk:The Haruhi Problem/@comment-37308828-20181026142226/@comment-61.72.45.210-20181026143224

n^2(n - 2)! + n - 3 is as same as n! + (n-1)! + (n-2)! + n - 3, because

n! + (n-1)! + (n-2)! + n-3 = (n-2)!(n^2 - n + n -1+1) + n - 3 = n^2(n - 2)! + n - 3.

You did a good job.