primeFactors function

List<int> primeFactors(
  1. int n
)

Prime factors (small numbers). Returns list of prime factors with multiplicity.

Implementation

List<int> primeFactors(int n) {
  if (n <= 1) return <int>[];
  final List<int> out = <int>[];
  int x = n.abs();
  for (int d = 2; d <= _isqrt(x); d++) {
    while (x % d == 0) {
      out.add(d);
      x ~/= d;
    }
  }
  if (x > 1) out.add(x);
  return out;
}