private static ulong CalculateByFactor(ulong a, ulong factors, ulong maxPrime, List<ulong> primes)
{
ulong sum = 0;
var b = a + (ulong)factors;
while (b <= maxPrime)
{
if (primes.BinarySearch(b) > -1)
{
double ratio = (double)(b + 1) / (a + 1);
double nextPrime = ratio * (b + 1) - 1;
if (nextPrime > maxPrime)
break;
ulong c = (ulong)Math.Round(nextPrime);
if (primes.BinarySearch(c) > -1)
{
if (CheckABC(a, b, c))
sum += a + b + c;
}
}
b += factors;
}
return sum;
}
private static ulong CalculateByPrimes(int i, List<ulong> primes, ulong a, ulong maxPrime)
{
ulong sum = 0;
for (int j = i + 1; j < primes.Count - 1; j++)
{
var b = primes[j];
double ratio = (double)(b + 1) / (a + 1);
double nextPrime = ratio * (b + 1) - 1;
if (nextPrime > maxPrime)
break;
ulong c = (ulong)Math.Round(nextPrime);
if (primes.BinarySearch(c) > -1)
{
if (CheckABC(a,b,c))
sum += a + b + c;
}
}
return sum;
}
