lower bound = 9

C(9,7,5) = 9

Method of Construction: cyclic covering found by search program

Lower Bound: Schonheim

  1  2  3  4  5  7  8
  2  3  4  5  6  8  9
  1  3  4  5  6  7  9
  1  2  4  5  6  7  8
  2  3  5  6  7  8  9
  1  3  4  6  7  8  9
  1  2  4  5  7  8  9
  1  2  3  5  6  8  9
  1  2  3  4  6  7  9