public static List<int> PrimeFactors(int n)
{
    if (n == 1)
    {
        return null;
    }
    var list = new List<int>();
    if (n % 2 == 0)
    {
        list.Add(2);

        while (n % 2 == 0)
        {
            n /= 2;
        }
    }

    for (int i = 3; i <= Math.Sqrt(n); i += 2)
    {
        if (n % i == 0)
        {
            list.Add(i);

            while (n % i == 0)
            {
                n /= i;
            }
        }
    }

    if (n > 2)
        list.Add(n);
    return list;
}

def primeFactors(n):
  global factors
  if(n==1):
    return
  elif((n%factors)== 0):
    print(factors)
    primeFactors(n//factors)
  else:
    factors+=1
    primeFactors(n)
factors = 2

public List<Integer> factorsOf(int n) {
  ArrayList<Integer> factors = new ArrayList<>();

  for (int d = 2; n > 1; d++)
    for (; n % d == 0; n /= d)
      factors.add(d);

  return factors;
}