lower bound = 81

C(22,3,2) = 81

Method of Construction: simple construction: combined (21,3,2) and (21,2,1)-coverings

Lower Bound: Schonheim

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