16 ≤ C(42,12,2) ≤ 17

Created by: LJCR

Method of Construction: Multiple of (21,6,2) covering

Lower Bound: Horsley, Theorem 11, r=4, d=3

  1  2  4  5 13 15 22 23 25 26 34 36
  1  3  6 16 18 20 22 24 27 37 39 41
  1  7  9 10 11 14 22 28 30 31 32 35
  1  8 12 17 19 21 22 29 33 38 40 42
  2  3 10 14 17 20 23 24 31 35 38 41
  2  5 11 16 17 21 23 26 32 37 38 42
  2  5 12 14 18 20 23 26 33 35 39 41
  2  6  7  8  9 19 23 27 28 29 30 40
  3  4  6 11 12 13 24 25 27 32 33 34
  3  5  6  8 10 19 24 26 27 29 31 40
  3  5  7  9 20 21 24 26 28 30 41 42
  3  6 14 15 17 21 24 27 35 36 38 42
  4  7  9 13 17 18 25 28 30 34 38 39
  4  8 13 14 16 19 25 29 34 35 37 40
  4 10 13 18 20 21 25 31 34 39 41 42
  7  9 10 12 15 16 28 30 31 33 36 37
  8 11 15 18 19 20 29 32 36 39 40 41