C(9,8,6) <=7

Method of construction: lex covering

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