>>62
さっきのはミスです。そしてスレチガイデス。
public class JavaScriptIsNotJava{
  public static void main(String[] args){
    int n = Integer.parseInt(args[0]);
    if(n<3) return;
    int sum = n*(n+1)/2;
    switch(n%3){
      case 0: sum -= (4+n-2)*(n/3-1); break;
      case 1: sum -= (4+n)*(n/3); break;
      case 2: sum -= (4+n-1)*(n/3); break;
    }
    double avg = (double)sum/n;
    System.out.println("total = "+sum);
    System.out.println("mean = "+avg);
  }
}