Find All combination with desired value

public static List<string> FindCombination(int range, int searchValue)
        {
            List<string> output = new List<string>();
            loop(1,1,"1");
            return output;
            void loop(long value, int iteration, string takenPath)
            {
                if (iteration == range && value == searchValue) //Escape from recursion when we reach the final number (itteration)
                {
                    output.Add($"{takenPath} = {value}");
                }
                else if (iteration < range)
                {
                    iteration += 1; //the next number
                    loop(value + iteration, iteration, takenPath + " + " + iteration); //add the number
                    loop(value - iteration, iteration, takenPath + " - " + iteration); //subtract the number

                    //adds the number to the end of the current number, example: 1 and 2 => 12, 4 and 5 => 45
                    if (value > 0)
                        loop(value * 10 + iteration, iteration, takenPath + iteration.ToString());
                    else
                        loop(value * 10 - iteration, iteration, takenPath + iteration.ToString());
                }
            }
        }