C(27,10,2) = 11

Method of Construction: lexicographic greedy covering

Lower Bound: Bounds for fixed number of blocks

  1  2  3  4  5  6  7  8  9 10
  1 11 12 13 14 15 16 17 18 19
  2 11 20 21 22 23 24 25 26 27
  3  4  5  6 12 13 14 20 21 22
  3  4  5  6 15 16 17 23 24 25
  7  8  9 10 12 13 14 23 24 25
  7  8  9 10 15 16 17 20 21 22
  3  4  5  6  7 11 18 19 26 27
  1  2 12 13 14 15 16 17 26 27
  1  2 18 19 20 21 22 23 24 25
  1  2  8  9 10 11 18 19 26 27