Finding Fibonacci sequence in C#. [Project Euler Exercise]

Question

I\'m having some trouble with this problem in Project Euler.

Here\'s what the question asks:

Each new term in the Fibonacci sequence is generated by adding t

Answer 1

     // count(user input) of Fibonacci numbers   
        int[] array = new int[20];
        array[0] = 0;
        array[1] = 1;

        Console.WriteLine(array[0] + "\n" + array[1]); 

        for (int i = 2; i < 20; i++)
        {
            array[i] = array[i - 1] + array[i - 2];
            Console.WriteLine(array[i]); 
        }

Answer 2

I think the question is written to say that you would add all the even numbers together while the numbers in the sequence don't exceed four million, meaning you would add 3,999,992.

Answer 3

Here's a nice way to find Fibonnaci numbers.

IEnumerable<BigInteger> Fibs()
{
    for(BigInteger a = 0,b = 1;;b = a + (a = b))
        yield return b;
}