= x + \displaystyle\sum_{n = 2}^{\infty}\displaystyle\frac{3^n-2^n}{n!}x^n + \displaystyle\sum_{n = 2}^{\infty}\displaystyle\frac{3^{n-1}-2^{n-1}}{(n-1)!}x^n + \displaystyle\frac{1}{2}\displaystyle\sum_{n = 2}^{\infty}\displaystyle\frac{3^{n-2}-2^{n-2}}{(n-2)!}x^n