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import java.util.ArrayList;
class Brilliant{
private static ArrayList primeFactors(long n){
ArrayList factors = new ArrayList();
while (n % 2 == 0){
factors.add(new Long(2));
n = n / 2;
}
for(long i = 3; i <= Math.sqrt(n); i = i + 2){
while (n % i == 0){
factors.add(new Long(i));
n = n / i;
}
}
if(n > 2)
factors.add(new Long(n));
return factors;
}
private static boolean isBrilliant(int n){
ArrayList factors = primeFactors(n);
return factors.size() == 2 && ((Long)factors.get(0)).toString().length() == ((Long)factors.get(1)).toString().length();
}
public static ArrayList nBrilliants(int n){
ArrayList brilliants = new ArrayList();
int i = 0;
do{
i++;
if(isBrilliant(i))
brilliants.add(new Integer(i));
}while(brilliants.size() < n);
return brilliants;
}
public static void main(String[] args){
ArrayList brilliants = Brilliant.nBrilliants(20);
for(int i = 0; i < brilliants.size() - 1; i++){
System.out.print(brilliants.get(i) + ", ");
}
System.out.println(brilliants.get(brilliants.size() - 1));
}
}
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