Find the wrong number in the series 7, 28, 63, 124, 215, 342, 511

Here the number follows the given rule 

  $$\begin{gathered} 2 3 - 1 , 3 3 - 1 , 4 3 - 1 , 5 3 - 1 , . . . \\ \end{gathered}$$

But 28 has been given in problem series.

so 28 is wrong number.