Hi,

What I've found out is that the most number of friends one person can have is 4, since they have the same number of friends. Also, the cases for 1 and 4 are the same, since for 4, you can take the cases for 1 and turn them into not-friends. Same for 2 and 3. So you have to first find out the cases for 1 and 2, then multiply by two.