var fibonacciNumbers = new List<int> {1, 1}; while (fibonacciNumbers.Count < 20) { var previous = fibonacciNumbers[fibonacciNumbers.Count - 1]; var previous2 = fibonacciNumbers[fibonacciNumbers.Count - 2]; fibonacciNumbers.Add(previous + previous2); } foreach(var item in fibonacciNumbers) Console.WriteLine(item);