lower bound = 26

C(13,3,2) = 26

Method of Construction: random greedy covering

Lower Bound: Schonheim

  9 12 13
  6 11 12
  7  9 11
  3  4 11
  4  5  7
  2  5 12
  5  8 11
  8 10 13
  1  3 12
  7  8 12
  2  3  7
  2 10 11
  2  6  9
  1  7 10
  3  8  9
  1  5  6
  5  9 10
  1 11 13
  4  6  8
  3  6 10
  2  4 13
  1  4  9
  1  2  8
  4 10 12
  6  7 13
  3  5 13