C(9,4,2) = 8

Created by: LJCR

Method of Construction: lex covering

Lower Bound: Horsley, Theorem 1, r=3, d=1

  1  2  3  4
  1  5  6  7
  2  5  8  9
  3  4  6  8
  3  4  7  9
  1  2  6  9
  1  2  7  8
  1  3  4  5