How many ways are there to arrange $n$ married couples in a line so that a husband and his wife are not together?
1513
In how many ways can n couples (husband and wife) be arranged on a bench so no wife would sit next to her husband?
120095
How many ways to split n elements in k groups?
144821
Number of ordered pairs of subsets
59419
Crafty solutions to the following limit
95378
Known bounds for the number of groups of a given order.
23322
Combinatorics Inclusion - Exclusion Principle
118022
Show that a group of order $180$ is not simple.
87345
How many ways so that $x+y+z\leq n$?
84910
Generate some number of lists of pairs given a list of people
60661
How to solve this combination problem quickly?
110436
ways to select a non-empty subset of these people, such that no two adjacent people are selected.
108941
Combinatorics Question Asking How Many Integer Solutions Given Different Restrictions
149939
Number of ordered pairs $(a,b)$ such that $ab \le 3600$
73575
Number of pairs of strings satisfying the given condition
48502
number of ordered pairs of integers $(x,y)$ satisfying the equation
100164
Tennis tournament proof that $n + 1$ players can form a line
79881
The Matching Problem/Derangements - n letters to n people