Counting number of perfect matching in bipartite graph.
107899
counting full bipartite matchings
40852
Number of ways of distributing $n$ identical objects among $r$ groups
68882
Path to Combinatorics Problem [$1.11$]
59247
How many connected graphs over V vertices and E edges?
107964
Simple combinatorics problem.
113953
Circular permutations with indistinguishable objects
114752
Number of permutations of a specific cycle decomposition
70252
Can a self-complementary graph on 100 vertices have precisely one vertex of degree 50?
118293
Strategy for determining the number of homomorphisms between two Groups
146933
Proving bipartition in a connected planar graph
54732
PMF of Matching Problem Hats
47240
An alternate solution to the hat-matching problem, probability of exactly $k$ matches
86067
A Variation of the even-town odd-town problem
37754
Number of vertices of a complete graph with $n$ edges
99931
Number of connected graphs on labeled vertices, counted according to parity
107110
Solving Rubik's cube and other permutation puzzles
51349
Minimal cut edges number in connected Eulerian graph.