import java.util.LinkedList; import java.util.List; import java.util.stream.Collectors; import java.util.Scanner; public class LabNumber { private static final int VALUE_THREE = 3; private static final int VALUE_ONE = 1; private int value; private List primeDividers; public LabNumber(int value) { this.value = value; } public boolean isLabNumber() { primeDividers = getListOfPrimeNumbers(value); if (primeDividers.size() == 0) return false; return true; } private List getListOfPrimeNumbers(int number) { int halfOfNumber = number / 2; List primeNumbers = new LinkedList<>(); for (int i = 1; i <= halfOfNumber; i++) { if (isPrime(i) && dividesNumber(i)) primeNumbers.add(i); } return primeNumbers; } private boolean dividesNumber(int i) { return value % Math.pow(i, 2) == 0; } private boolean isPrime(int value) { if (value <= VALUE_ONE) return false; else if (value <= VALUE_THREE) return true; else if (modTwoOrThreeEqualsZero(value)) return false; int iterator = 5; while (iterator * iterator <= value) { if (modByIteratorIsEqualZero(value, iterator)) return false; iterator += 6; } return true; } private boolean modByIteratorIsEqualZero(int value, int iterator) { return value % iterator == 0 || value % (iterator + 2) == 0; } private boolean modTwoOrThreeEqualsZero(int value) { return value % 2 == 0 || value % 3 == 0; } @Override public String toString() { return "LabNumber{" + "number=" + value + ", has prime dividers=" + primeDividers + '}'; } } public class LabNumberMain { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int number = sc.nextInt(); List labNumbers = new LinkedList<>(); LabNumber labNumber; labNumber = new LabNumber(number); if(labNumber.isLabNumber()) System.out.println(labNumber); else System.out.println(number + " is not a lab number"); for (int i = 0; i < number;i++) { labNumber = new LabNumber(i); if(labNumber.isLabNumber()) labNumbers.add(labNumber); } labNumbers.forEach(System.out::println); } }

Lab number