31 ≤ C(18,7,3) ≤ 32
Created by: Franco Atzeni
Method of Construction: cyclic covering found by search program
Lower Bound: Schonheim
1 2 3 5 6 9 11
1 2 4 5 8 10 16
1 2 5 7 13 14 15
1 2 5 10 12 17 18
1 3 4 7 9 15 16
1 3 8 9 12 17 18
1 3 9 10 11 13 14
1 4 6 12 13 14 16
1 4 9 11 16 17 18
1 6 7 10 15 17 18
1 6 8 13 14 17 18
1 7 8 9 11 12 15
2 3 4 6 7 10 12
2 3 6 8 14 15 16
2 3 6 11 13 17 18
2 4 9 10 13 17 18
2 4 10 11 12 14 15
2 7 8 11 16 17 18
2 7 9 14 15 17 18
2 8 9 10 12 13 16
3 4 5 7 8 11 13
3 4 7 12 14 17 18
3 5 10 11 14 17 18
3 5 11 12 13 15 16
3 8 10 15 16 17 18
4 5 6 8 9 12 14
4 5 8 13 15 17 18
4 6 11 12 15 17 18
5 6 7 9 10 13 15
5 6 9 14 16 17 18
5 7 12 13 16 17 18
6 7 8 10 11 14 16