Dickson polynomial
From specialfunctionswiki
The Dickson polynomials of the first kind are $$\left\{ \begin{array}{ll} D_0(x,\alpha) &=2 \\ D_n(x,\alpha) &=\displaystyle\sum_{k=0}^{\lfloor \frac{n}{2} \rfloor} \dfrac{n}{n-k} {{n-p} \choose p} (-\alpha)^p x^{n-2k}. \end{array} \right.$$
The Dickson polynomials of the second kind are $$\left\{ \begin{array}{ll} E_0(x,\alpha) &= 1 \\ E_n(x,\alpha) &= \displaystyle\sum_{k=0}^{\lfloor \frac{n}{2} \rfloor} {{n-k} \choose k} (-\alpha)^k x^{n-2k}. \end{array} \right.$$
