C(19,9,2) = 7

Method of Construction: lex covering

Lower Bound: Schonheim

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  1 10 11 12 13 14 15 16 17
  2  3  4  5 10 11 12 18 19
  6  7  8  9 13 14 15 18 19
  2  3  4  5 13 14 15 16 17
  6  7  8  9 10 11 12 16 17
  1  2  3  4  5 16 17 18 19