A pyramid $ABCDS$ in which all edges have different lengths and $|AS|+|CS|=|BS|+|DS|$
50748
A pyramid $ABCDS$ in which all edges have different lengths and $|AS|+|CS|=|BS|+|DS|$
31854
Proof - raising adjacency matrix to $n$-th power gives $n$-length walks between two vertices
117020
Regular $n$-gon in the plane with vertices on integers?
43845
Partitioning the edges of $K_n$ into $\lfloor \frac n6 \rfloor$ planar subgraphs
92554
How many lattice paths are there from $(0,0)$ to $(2n,2n)$ that avoids odd points
97630
A graph which is not a single block has at least two leaf blocks
137322
Construction of a triangle-free graph of chromatic number $1526$
8458
Combinatorics problem based on Ferrers graph
33822
Is there a monoid structure on the set of paths of a graph?
63571
The Mississipi counting problem, this time in circle
116153
The Notorious Triangle Problem
151326
Concurrency of the heights of a tetrahedron with opposite edges perpendicular.
127701
How many distinct ways are there to $2$-color the $8$ vertices of a cube?
92267
Adjacency matrix and existence of triangle
79777
An olympiad Geometry problem involving triangles
32260
Alternating Sum of Cubes
134242
Graph partition that span a third of edges