public static double P(double n, long x)
else return ((2*n-1)*x*P(n-1, x)-(n-1)*P(n-2, x))/n;
public static void Main (string[] args)
Console.Write("Enter x: ");
int x = int.Parse (Console.ReadLine());
Console.Write("Enter n: ");
int n = int.Parse (Console.ReadLine());
Console.WriteLine(P(n, x));