C(9,7,6) <=16

Method of construction: lex covering

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