lower bound = 54

C(18,3,2) = 54

Method of Construction: random greedy covering

Lower Bound: Schonheim

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