C(28,4,2) = 63
Method of Construction: simple construction: induced on c(29,5,3) covering
Lower Bound: Schonheim
1 8 15 22
2 9 16 23
3 10 17 24
4 11 18 25
5 12 19 26
6 13 20 27
7 14 21 28
2 4 12 13
3 5 13 14
4 6 8 14
5 7 8 9
1 6 9 10
2 7 10 11
1 3 11 12
9 11 19 20
10 12 20 21
11 13 15 21
12 14 15 16
8 13 16 17
9 14 17 18
8 10 18 19
17 21 23 25
15 18 24 26
16 19 25 27
17 20 26 28
18 21 22 27
15 19 23 28
16 20 22 24
5 6 24 28
6 7 22 25
1 7 23 26
1 2 24 27
2 3 25 28
3 4 22 26
4 5 23 27
3 7 16 18
1 4 17 19
2 5 18 20
3 6 19 21
4 7 15 20
1 5 16 21
2 6 15 17
10 14 26 27
8 11 27 28
9 12 22 28
10 13 22 23
11 14 23 24
8 12 24 25
9 13 25 26
1 14 20 25
2 8 21 26
3 9 15 27
4 10 16 28
5 11 17 22
6 12 18 23
7 13 19 24
1 13 18 28
2 14 19 22
3 8 20 23
4 9 21 24
5 10 15 25
6 11 16 26
7 12 17 27