It was pointed out that the sequence generator could be written as an infinite sequence to allow .Skip(), .Take(), .ElementAt(), etc. Here is the infinite sequence version.
public static class Fibonacci
{
public static IEnumerable<BigInteger> Generate()
{
yield return 1;
yield return 1;
BigInteger n1 = 1, n2 = 1;
while(true)
{
BigInteger n3 = n1 + n2;
n1 = n2;
n2 = n3;
yield return n3;
}
}
}
