lower bound = 63

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