29 ≤ C(15,8,4) ≤ 30

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

Lower Bound: Schonheim

  1  2  5  6 11 12 14 15
  3  4  7  8  9 10 13 14
  1  4  5  8 10 11 14 15
  1  2  3  6  7  9 12 13
  1  3  6  8  9 10 11 14
  2  4  5  7 10 12 13 15
  1  3  6  8 10 12 13 15
  2  4  5  6  7  9 11 14
  1  2  3  4  9 10 11 12
  3  5  6  7  8 13 14 15
  1  2  7  8 11 12 13 14
  1  3  4  5  6  9 10 15
  1  4  6  7 10 11 13 14
  2  3  5  8  9 12 14 15
  1  2  3  4  5  6  7  8
  3  9 10 11 12 13 14 15
  1  4  5  8  9 12 13 14
  2  3  6  7 10 11 14 15
  1  2  7  8  9 10 12 15
  3  4  5  6 11 12 13 14
  1  3  5  7  9 11 13 15
  2  4  6  8 10 12 13 14
  1  2  3  4  6 13 14 15
  5  6  7  8  9 10 11 12
  1  4  6  7  9 12 14 15
  2  3  5  8 10 11 13 14
  1  3  4  5  7 10 12 14
  2  4  6  8  9 11 13 15
  1  2  5  6  9 10 13 14
  3  4  7  8 11 12 14 15