20 ≤ C(40,10,2) ≤ 21

Created by: LJCR

Method of Construction: Multiple of (20,5,2) covering

Lower Bound: Schonheim

  1  2  3  4  5 21 22 23 24 25
  1  2  7 15 16 21 22 27 35 36
  1  2 11 14 17 21 22 31 34 37
  1  3  8 12 20 21 23 28 32 40
  1  4  9 10 19 21 24 29 30 39
  1  5  6 13 18 21 25 26 33 38
  1  6  7  8  9 21 26 27 28 29
  1 10 15 18 20 21 30 35 38 40
  1 12 13 16 19 21 32 33 36 39
  2  6 10 11 12 22 26 30 31 32
  2  8 14 18 19 22 28 34 38 39
  2  9 13 17 20 22 29 33 37 40
  3  6 15 17 19 23 26 35 37 39
  3  7 10 13 14 23 27 30 33 34
  3  9 11 16 18 23 29 31 36 38
  4  6 14 16 20 24 26 34 36 40
  4  7 12 17 18 24 27 32 37 38
  4  8 11 13 15 24 28 31 33 35
  5  7 11 19 20 25 27 31 39 40
  5  8 10 16 17 25 28 30 36 37
  5  9 12 14 15 25 29 32 34 35