Let $\overrightarrow{a}, \overrightarrow{b}$ and $\overrightarrow{c}$ be three non-zero vectors such that no two of these are collinear. If the vector $\overrightarrow{a} + 2 \overrightarrow{b} $ is collinear with $\overrightarrow{c}$ and $\overrightarrow{b} + 3 \overrightarrow{c}$ is collinear with $\overrightarrow{a}$ ($\lambda$ being some non-zero scalar) then $\overrightarrow{a} + 2\overrightarrow{b} + 6 \overrightarrow{c}$ equals
