30 ≤ C(15,6,3) ≤ 31

Method of Construction: simulated annealing covering

Lower Bound: Schonheim

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