Sorted edges (pairs of vertices a and b with a < b) on an octahedron.
1, 2, 1, 3, 1, 4, 1, 5, 2, 3, 2, 5, 2, 6, 3, 4, 3, 6, 4, 5, 4, 6, 5, 6
1
The vertices are labeled 1 to 6. Each edge appears only once.
T. D. Noe, Plot of 12 pairs
T. D. Noe, Points on an octahedron
Eric W. Weisstein, MathWorld: Octahedron
nonn,full
T. D. Noe, Jan 29 2016