lower bound = 15

C(12,6,3) = 15

Method of Construction: lex covering

Lower Bound: Handbook of Combinatorial Designs section on coverings

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