【程式語言】JAVA的第六堂課 ｜1*2+2*3+3*4+4*5+5*6+…+ n*(n-1)遞迴練習題

public class hw7_23 {
    public static int rsum(int n) {
        if ( n == 1 || n == 2) {
            return 2;
        }
        else {
            return n * (n-1) + rsum(n-1); 
        }
    }
    public static void main(String[] args) {
        System.out.println(rsum(5));
    }
}

Result: