UVA - 160 - Factors and Factorials

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedList;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb = new StringBuffer();
        String m="";
        int[][]arr=new int[101][100];
        for(int i=2;i<arr.length;i++){
            System.arraycopy(arr[i-1], 2, arr[i], 2, 100 - 2);
            LinkedList<Integer> list=primeFactors(i);
            while(!list.isEmpty()){
                int temp=list.remove();
                arr[i][temp]++;
            }
        }
        while(true){
            int x=Integer.parseInt(br.readLine());
            if(x==0){
                break;
            }
            String str=String.format("%3d! =", x);
            sb.append(str);
            int counter=0;
            boolean flag=false;
            for(int i=2;i<100;i++){
                if(arr[x][i]>0){
                    if(flag){
                       sb.append("      ");
                       flag=false;
                    }
                    str=String.format("%3d", arr[x][i]);
                    sb.append(str);
                    counter++;
                    if(counter%15==0){
                        sb.append("\n");
                        flag=true;
                    }
                }
            }
            if(!flag){
                sb.append("\n");
            }
        }
        System.out.print(sb);
    }
   
    static LinkedList<Integer> primeFactors(int x){
        LinkedList<Integer> list=new LinkedList<Integer>();
        if(x<0){
            list.add(-1);
        }
        int temp=Math.abs(x);
        boolean notprime=false,entered=false;
        while(temp>1 &&!notprime){
            entered=false;
            for(int i=2;i<Math.sqrt(temp)+1;i++){
                if(temp%i==0){
                    list.add(i);
                    temp/=i;
                    notprime=false;
                    entered=true;
                    break;
                }
            }
            if(!entered)
                 notprime=true;
        }
        if(notprime){
                list.add(temp);
            }
        return list;
    }
}