当w的w次方等于w的mod（n）时  就输出！！

import java.math.BigInteger;
import java.util.Scanner;
public class cSong {
   

        public static void main(String[] args) {
            
            for(int j=0;j<100;j++){
             Scanner reader=new Scanner(System.in);
             System.out.println("Please input n:");
             BigInteger n=new BigInteger(reader.next());
             BigInteger a=new BigInteger("1");
             BigInteger b=a;
             BigInteger w = b;
             if(isPrime(n.intValue())){
               
                 for(w=a;w.intValue()<n.intValue();w.add(a)){
                     
                     BigInteger m;
                    m=w.pow(w.intValue());
                    
                 if(m.equals(w.divideAndRemainder(n))){
                     System.out.println(w+"的"+w+"幂次方"+"="+w+"mod"+n);
                 }
                 }
             }else {
                System.out.println("n不是素数");
             }
    }
}
        public static boolean isPrime(int n)
        {
            if(n < 2) return false;

            for(int i = 2; i < n; ++i)
                if(n%i == 0) return false;
            return true;
        }
}