C(18,12,4) = 12

Method of Construction: lex covering

Lower Bound: Sidorenko; 1996

  1  2  3  4  5  6  7  8  9 10 11 12
  1  2  3  4  5  6 13 14 15 16 17 18
  7  8  9 10 11 12 13 14 15 16 17 18
  1  2  3  4  7  8  9 10 13 14 15 16
  1  2  5  6  7  8 11 12 13 14 17 18
  3  4  5  6  9 10 11 12 15 16 17 18
  1  2  3  4  7  8 11 12 15 16 17 18
  1  2  5  6  9 10 11 12 13 14 15 16
  3  4  5  6  7  8  9 10 13 14 17 18
  1  2  3  4  9 10 11 12 13 14 17 18
  1  2  5  6  7  8  9 10 15 16 17 18
  3  4  5  6  7  8 11 12 13 14 15 16