public static IEnumerable <long> PrimeNumberBelow(int upperBound)
{
yield return(2);
long num = 3;
do
{
if (Factors.IsPrime(num))
{
yield return(num);
}
num += 2;
} while (num < upperBound);
}
public static IEnumerable <long> PrimeNumberNth(int index)
{
yield return(2);
long num = 3;
int i = 1;
do
{
if (Factors.IsPrime(num))
{
yield return(num);
i++;
}
num += 2;
} while (i < index);
}