public override string Solve() { int x; List <int> amicableList = new List <int>(); for (x = 2; x < 10000; x++) { var factorListX = AdvancedMath.Factor(x); var sumX = factorListX.Sum() - factorListX[factorListX.Count - 1]; var factorListY = AdvancedMath.Factor(sumX); var sumY = factorListY.Sum() - factorListY[factorListY.Count - 1]; if (sumY == x && sumY != sumX) { amicableList.Add(x); } } return("Sum of all amicable numbers under 10000 is: " + amicableList.Sum()); }