11 ≤ C(18,10,3) ≤ 12

Method of Construction: simple construction: multiple of smaller covering

Lower Bound: Schonheim

  1  2  3  4  5 10 11 12 13 14
  1  2  6  7  8 10 11 15 16 17
  3  4  6  7  9 12 13 15 16 18
  1  3  5  8  9 10 12 14 17 18
  2  4  5  6  8 11 13 14 15 17
  2  4  5  7  9 11 13 14 16 18
  1  3  5  6  7 10 12 14 15 16
  1  4  7  8  9 10 13 16 17 18
  2  3  6  8  9 11 12 15 17 18
  1  2  4  6  9 10 11 13 15 18
  2  3  4  7  8 11 12 13 16 17
  5  6  7  8  9 14 15 16 17 18