lower bound = 50

C(25,4,2) = 50

Method of Construction: simple construction: induced on c(26,5,3) covering

Lower Bound: Schonheim

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