public class Test2 {

    public static double[] function(double l, int n) {

        double result[] = new double[10];

        double x = l*n;
        if (n < 0) {
            return null;
        } else if (n > 0) {
            result = new double[n];
        } else  {
            return null;
        }

    long f = 1;

    for (int k = 0; k < n; k++) {
        result[k] = Math.pow(l,k) / f * Math.exp(-1);
        if (k > 0) {
            f*=k;
            System.out.println("P(" + k + ") =" + result[k]);
        } else if (k == 0) {
            System.out.println("P(" + k + ") =" + result[k]);
            x *= l;
        } else if (k < 0) {
            throw new IllegalArgumentException("Fehler");
            System.out.println("P(" + k + ") =" + x);
        }
    }

    return result;
    }
}


/*

for (int k = 0; k < n; k++) {
    result[k] = Math.pow(l,k); / f * Math.exp(-1);
    System.out.println("P(" + k + ") =" + result[k]);
    f *=k;
    */