public static long Problem10()
{
long[] primes = Helpers.PrimesBelow(2000000).ToArray();
long sum = 0;
for (int i = 0; i < primes.Length; i++)
{
sum += primes[i];
}
return(sum);
}
public static long Problem3(long target)
{
long[] primes = Helpers.PrimesBelow(Convert.ToInt64(Math.Sqrt(target))).ToArray();
long lastPrime = 2;
long index = 0;
while (target != 1)
{
if (target % primes[index] != 0)
{
index++;
lastPrime = primes[index];
}
else
{
target = target / primes[index];
}
}
return(lastPrime);
}
