lower bound = 28

C(23,5,2) = 28

Method of Construction: lex covering

Lower Bound: Schonheim

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