private static List <double> FindEvenDivisors(double max) { List <double> primeFactors = new List <double> { }; for (double i = 2; i <= max; i++) { if (Problem3.IsPrimeFactor(i, primeFactors)) { primeFactors.Add(i); } else { List <double> nPrimeFactors = FindPrimeFactors(i, primeFactors); primeFactors = AddMissingFactors(nPrimeFactors, primeFactors); } } return(primeFactors); }