C(25,8,2) = 13

Method of Construction: simple construction: deleted element from c(v+1,k,t) covering

Lower Bound: Schonheim

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