C(30,9,2) = 15
Method of Construction: simple construction: induced on c(31,10,3) covering
Lower Bound: Handbook of Combinatorial Designs section on coverings
3 4 11 12 13 15 18 19 22
5 9 13 15 17 24 26 29 30
4 8 9 10 17 19 20 26 28
1 4 5 14 16 19 24 25 27
1 3 8 11 22 25 28 29 30
10 12 14 16 18 20 27 29 30
2 3 7 9 17 22 23 26 27
2 3 7 9 11 14 16 26 27
2 7 9 11 14 16 17 22 23
6 8 13 14 15 16 21 27 28
3 5 6 10 11 20 21 22 24
2 5 7 8 12 18 23 24 28
1 2 7 10 13 15 20 23 25
2 4 6 7 19 21 23 29 30
1 6 9 12 17 18 21 25 26