lower bound = 7

C(15,7,2) = 7

Method of Construction: lex covering

Lower Bound: Schonheim

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