C(17,9,2) <=6

Method of construction: lex covering

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