Answer to Question #26088 in Combinatorics | Number Theory for Ritvik

Question

how many integers from 1 to 19999 have exactly 15 divisors ?

Answer 1

package divisors; import java.util.ArrayList;
import java.util.List;

public class Divisors {

public static void main(String[] args) {

int number = 19999;
int answer =countdivisor(number);
System.out.print("Answer:");
System.out.println(answer);
}

public static int countdivisor(int number) {
List<Integer> list = newArrayList();
int j = 0;
int countOfNumbers = 0;
int divisors = 0;
while (j <= number) {
divisors = 0;
for (int i = 1; i<= j; i++) {
if(j % i == 0) {
divisors++;
}
}
if (divisors ==15) {
countOfNumbers++;
list.add(j);
}
j++;
}
System.out.println("List ofnumbers:");
for (Integer i : list) {
System.out.println(i);
}
System.out.println("");
return countOfNumbers;
}
}

List of numbers:
144
324
400
784
1936
2025
2500
2704
3969
4624
5625
5776
8464
9604
9801
13456
13689
15376
16384

Answer:19