\[\boxed{\mathbf{17.}}\]
\[6 \cdot 2 + 6 = 12 + 6 = 18\]
\[6 \cdot 3 + 6 = 18 + 6 = 24\]
\[6 \cdot 4 + 6 = 24 + 6 = 30\]
\[6 \cdot 5 + 6 = 30 + 6 = 36\]
\[6 \cdot 6 + 6 = 36 + 6 = 42\]
\[6 \cdot 7 + 6 = 42 + 6 = 48\]
\[6 \cdot 8 + 6 = 48 + 6 = 54\]
\[6 \cdot 9 + 6 = 54 + 6 = 60\]