Find all the Fibonacci numbers for a given limit

        public static List<int> DoGetFibonacci(int n)
        {
            int a = 1, b = 2, c = 0;
            List<int> series = new List<int>();

            series.Add(a);
            series.Add(b);

            while (series.Count < n)
            {
                c = a + b;
                a = b;
                b = c;
                
                series.Add(c);
            }

            return series;
        }
        

How it works:

The core of Fibonacci series is adding up previous two numbers a and b to form the next number c. Taking this as the base we build the logic and put it in a loop to iteratively generate the series.