14 ≤ C(28,14,3) ≤ 15

Method of Construction: simple construction: multiple of smaller covering

Lower Bound: Schonheim

  1  5  7  8  9 10 12 15 19 21 22 23 24 26
  3  6  7  9 10 13 14 17 20 21 23 24 27 28
  1  4  6  7  8 11 13 15 18 20 21 22 25 27
  2  4  7  9 10 11 13 16 18 21 23 24 25 27
  1  2  3  7  8 13 14 15 16 17 21 22 27 28
  3  4  5  7 11 12 14 17 18 19 21 25 26 28
  2  5  6  8 10 11 14 16 19 20 22 24 25 28
  1  2  3 10 11 12 13 15 16 17 24 25 26 27
  2  3  5  6  7 12 13 16 17 19 20 21 26 27
  3  4  5  7  8 10 13 17 18 19 21 22 24 27
  1  2  5  9 11 13 14 15 16 19 23 25 27 28
  2  4  8  9 12 13 14 16 18 22 23 26 27 28
  1  4  6 10 12 13 14 15 18 20 24 26 27 28
  3  5  6  8  9 11 12 17 19 20 22 23 25 26
  1  2  3  4  5  6  9 15 16 17 18 19 20 23