17 ≤ C(26,12,3) ≤ 18

Created by: Jan de Heer

Lower Bound: Horsley-Singh, Theorem 18a, s=1

  1  2  3  4  5  6  7  8  9 10 24 25
  1  2  3  4 11 12 13 14 15 18 19 25
  1  2  3  4 11 12 13 14 15 19 23 26
  1  2  3  4 16 17 20 21 22 23 25 26
  1  2  5  6  9 10 11 13 15 17 19 21
  1  2  5  6  9 10 12 14 16 18 20 22
  1  2  5  6  9 10 12 14 20 22 23 26
  1  2  7  8 11 13 15 16 19 20 22 24
  1  2  7  8 12 14 17 18 21 23 24 26
  3  4  5  6  7  8 11 12 13 14 16 21
  3  4  5  6  7  8 15 17 18 19 20 22
  3  4  5  6  7  8 15 19 20 22 23 26
  3  4  9 10 11 12 13 14 17 20 22 24
  3  4  9 10 15 16 18 19 21 23 24 26
  5  6 11 13 18 20 21 22 23 24 25 26
  5  6 12 14 15 16 17 19 23 24 25 26
  7  8  9 10 11 13 16 17 18 23 25 26
  7  8  9 10 12 14 15 19 20 21 22 25