public static List<Integer> primeFactors(int number) {
        List<Integer> fs = new ArrayList<>();
        IntStream.rangeClosed(2, number / 2).filter(P31::isPrime).forEach(f -> {
            int n = number;
            while (n % f == 0) {
                n = n / f;
                fs.add(f);
            }
        });
        return fs;
    }
(**) Determine the prime factors of a given positive integer.
java8/src/main/java/com/shekhargulati/ninetynine_problems/_02_arithmetic/P32.java