\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
For the sequence given in the table below, find the explicit formula for \(u_n\).
\(n\) 0 1 2 3 4
\(u_n\) \(0\) \(3\) \(6\) \(9\) \(12\)
\(u_n=\)