16 ≤ C(31,9,2) ≤ 17
Created by: Rade Belic and Jan de Heer
Lower Bound: Horsley, Theorem 1, r=4, d=2
1 2 3 4 5 6 19 20 21
1 2 7 8 9 10 22 23 24
1 2 11 12 13 14 25 26 27
1 2 15 16 17 18 28 29 31
1 2 15 16 17 18 28 30 31
3 4 7 8 13 14 25 29 30
3 4 9 10 11 12 26 28 31
3 4 9 10 17 18 24 25 27
3 4 11 12 15 16 22 23 24
5 6 7 8 13 14 24 28 31
5 6 7 8 15 16 25 26 27
5 6 9 10 11 12 22 29 30
5 6 13 14 17 18 22 23 26
7 8 11 12 17 18 19 20 21
9 10 13 14 15 16 19 20 21
19 20 21 22 23 25 27 28 31
19 20 21 23 24 26 27 29 30