Hey @AkivaWeinberger @TedShifrin
Could you take a look at my question: http://math.stackexchange.com/questions/1667075/symmetric-group-find-the-elements-of-the-set ?
I have thought the following:
We have $$\sigma \cdot (1, \ldots, n) \cdot \sigma^{-1} = \big(\sigma(1), \sigma(2), \ldots, \sigma(n)\big) \\ \Rightarrow \sigma \cdot (1, \ldots, n) \cdot \sigma^{-1} \cdot \sigma = \big(\sigma(1), \sigma(2), \ldots, \sigma(n)\big)\cdot \sigma \\ \Rightarrow \sigma \cdot (1, \ldots, n) = \big(\sigma(1), \sigma(2), \ldots, \sigma(n)\big)\cdot \sigma $$