14 ≤ C(28,18,4) ≤ 16

Created by: LJCR

Method of Construction: Multiple of (14,9,4) covering

Lower Bound: Schonheim

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