C(21,11,2) = 6

Method of Construction: lex covering

Lower Bound: Bounds for fixed number of blocks

  1  2  3  4  5  6  7  8  9 10 11
  1 12 13 14 15 16 17 18 19 20 21
  2  3  4  5  6  7 12 13 14 15 16
  2  3  4  5  6  7 17 18 19 20 21
  8  9 10 11 12 13 14 15 16 17 18
  1  2  3  4  8  9 10 11 19 20 21