public static int Main()
{
var links = new HashSet <(long p1, long p2)>();
var primeSet = new HashSet <long>(PrimeUtils.FilePrimes);
foreach (var prime in PrimeUtils.FilePrimes)
{
links.UnionWith(GetLinks(prime, primeSet));
}
var currPrime = primeSet.Max();
for (var i = 0; i < 1000000; i++)
{
currPrime = PrimeUtils.NextPrimeBasic(currPrime);
links.UnionWith(GetLinks(currPrime, primeSet));
primeSet.Add(currPrime);
}
links = new HashSet <(long p1, long p2)>(CompressLinks(links));
var conn4 = ConnectedSignatures4(links).OrderBy(x => x.Item1 + x.Item2 + x.Item3 + x.Item4).ToArray();
var conn5 = ConnectedSignatures5(links, conn4).OrderBy(x => x.Item1 + x.Item2 + x.Item3 + x.Item4 + x.Item5).ToArray();
return(0);
}
static void Main(string[] args)
{
//n^2 + an + b
long productForLongestPrimeCoefficients = 0;
int longestValueForN = 0;
PrimeUtils pu = new PrimeUtils();
int LIMIT = 1000;
int START = -1000;
for (int coefficientA = START; coefficientA <= LIMIT; coefficientA++)
{
for (int coefficientB = START; coefficientB <= LIMIT; coefficientB++)
{
int n = 0;
int count = 0;
long solution = 0;
bool endLoop = false;
long product;
while (!endLoop)
{
solution = calculateQuadratic(n, coefficientA, coefficientB);
if (pu.isPrime(solution))
{
n++;
//Console.WriteLine(solution + " is prime");
count++;
}
else
{
if (coefficientA == 1 && coefficientB == 41)
{
/// Console.WriteLine("a is 1, b is 41, n is " + count);
}
product = (coefficientA) * (coefficientB);
if (longestValueForN < count)
{
longestValueForN = count;
productForLongestPrimeCoefficients = product;
Console.WriteLine("Found new highest length at: a = " + coefficientA + " b = " + coefficientB + " with a length of " + count + " and a product of " + product);
}
endLoop = true;
}
}
}
}
Console.WriteLine("finished");
Console.ReadLine();
}
public void Test01()
{
// if n < 3,317,044,064,679,887,385,961,981, it is enough to test a = 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, and 41. @ wiki
for (int c = 0; c < 10000; c++)
{
string s = string.Format("331704406467988738596{0:D4}", c);
Console.WriteLine(s + " ==> " + PrimeUtils.IsPrime_M(Common.ToBigInteger(s)));
}
}
public static bool SatisfiesConjecture(long n, SortedSet <long> primes, SortedSet <long> twiceSquares)
{
while (primes.Max < n)
{
primes.Add(PrimeUtils.NextPrime(primes));
}
while (twiceSquares.Max < n)
{
twiceSquares.Add(2 * (long)Math.Pow(twiceSquares.Count, 2));
}
return(primes.Any(p => twiceSquares.Contains(n - p)));
}
private void IncreaseBitSetCapacity(Int32 count)
{
Int32 size = PrimeUtils.NextPrime(count);
if (size > _freeIdSize)
{
size = _freeIdSize;
}
BitSet newBitSet = new BitSet(size);
newBitSet.Or(_freeIds);
_freeIds = newBitSet;
}
private void GenerateDHPrimes()
{
DHPrime = PrimeUtils.GeneratePseudoPrime(DiffiePrimesBitSize, DiffieWitnesses);
DHGenerator = PrimeUtils.GeneratePseudoPrime(DiffiePrimesBitSize, DiffieWitnesses);
// Prime needs to be bigger than the generator.
if (DHGenerator > DHPrime)
{
var temp = DHPrime;
DHPrime = DHGenerator;
DHGenerator = temp;
}
}
public Boolean Initialize()
{
try
{
_freeIds = new BitSet(PrimeUtils.NextPrime(100000));
_freeIds.Clear();
_freeIdCount = _freeIdSize;
foreach (UInt32 usedObjectId in ExtractUsedObjectIdTable())
{
if (_exclude.Contains(usedObjectId))
{
continue;
}
Int32 objectId = (Int32)(usedObjectId - _firstId);
if (usedObjectId < _firstId)
{
#if NLOG
_log.Warn("{0}: Object ID {1} in DB is less than {2}", _name, usedObjectId, _firstId);
#endif
continue;
}
if (objectId >= _freeIds.Count)
{
IncreaseBitSetCapacity(objectId + 1);
}
_freeIds.Set(objectId);
Interlocked.Decrement(ref _freeIdCount);
}
_nextFreeId = _freeIds.NextClear(0);
#if NLOG
_log.Info("{0} successfully initialized", _name);
#endif
}
catch (Exception e)
{
#if NLOG
_log.Error("{0} could not be initialized correctly", _name);
_log.Error(e);
#endif
return(false);
}
return(true);
}
public static long Get()
{
var pandigit = 9;
var prime = 0;
while (prime == 0)
{
var arr = SetUtils.LexicographicPermutations(Enumerable.Range(1, pandigit--))
.Select(x => x.Reverse().DigitsToNumber())
.Reverse()
.ToArray();
prime = arr.FirstOrDefault(x => PrimeUtils.IsPrime(x));
}
return(prime);
}
private void startBut_Click(object sender, EventArgs e)
{
int colSize = int.Parse(numSizeText.Text);
countText.Clear();
InitVals(vals, colSize);
var task = Task.Run(() => {
int size = PrimeUtils.CountPrimes(vals, colSize);
return(size);
});
task.ContinueWith((ant) => {
int res = ant.Result;
this.countText.Text = res.ToString();
startBut.Enabled = true;
}, TaskScheduler.FromCurrentSynchronizationContext());
startBut.Enabled = false;
}
public static IEnumerable <long[]> Main()
{
var primes = new SortedSet <long> {
2, 3, 5, 7
};
var primesTodo = new SortedSet <long>();
var digits = 2;
while (true)
{
var maxForDigits = Math.Pow(10, digits);
while (primes.Max < maxForDigits)
{
var nxt = PrimeUtils.NextPrime(primes);
if (nxt >= maxForDigits)
{
break;
}
primes.Add(nxt);
primesTodo.Add(nxt);
}
while (primesTodo.Any())
{
var todo = primesTodo.First();
foreach (var family in Replacements(todo))
{
var familyPrimes = family.Where(x => primes.Contains(x)).ToArray();
yield return(familyPrimes);
primesTodo.ExceptWith(familyPrimes);
}
}
digits++;
}
}
static void Main(string[] args)
{
HashSet <int> circularPrimes = new HashSet <int>();
PrimeUtils pu = new PrimeUtils();
for (int i = 0; i < 1000001; i++)
{
int len = i.ToString().Length - 1;
int j = 0;
int num = i;
bool stillPrime = true;
while (stillPrime && j <= len)
{
if (pu.IsPrime(num))
{
//Console.WriteLine(num + " is prime");
num = RotateDigits(num);
j++;
}
else
{
stillPrime = false;
}
}
if (stillPrime)
{
Console.WriteLine("Found circular prime: " + i);
circularPrimes.Add(i);
}
}
Console.WriteLine("Number of Values: " + circularPrimes.Count);
Console.ReadLine();
}
public static long Main(int distinctCount)
{
var primes = new List <long> {
2
};
var count = 0;
var n = 2L;
while (count != distinctCount)
{
if (primes.Last() < n)
{
primes.Add(PrimeUtils.NextPrime(primes));
}
// stop collecting factors if more than distinct count
var primeFactors = GetPrimeFactors(n, primes).TakeWhile((x, i) => i <= distinctCount);
count = primeFactors.Count() == distinctCount ? count + 1 : 0;
n++;
}
return(n - distinctCount);
}
static Boolean CheckTruncPrime(int n)
{
PrimeUtils pu = new PrimeUtils();
int num = n;
while (num != 0)
{
if (!pu.IsPrime(num))
{
return(false);
}
else
{
num /= 10; //right to left truncate
}
}
num = n;
string digits = n.ToString().Substring(1); //remove leading digit
while (digits != "")
{
if (!pu.IsPrime(int.Parse(digits)))
{
return(false);
}
if (digits.Length == 1) //Checked the string in above statement.
{
digits = "";
}
else
{
digits = digits.Substring(1);
}
}
return(true);
}
public static long QuadraticPrimeCount(int a, int b)
{
return(InfiniteSet.NaturalNumbers(true).SkipWhile(n => PrimeUtils.IsPrime(n * n + a * n + b)).First());
}
private void GenerateDHKeys()
{
DHPrivate = PrimeUtils.GeneratePseudoPrime(DiffieKeyBitSize, DiffieWitnesses);
DHPublic = BigInteger.ModPow(DHGenerator, DHPrivate, DHPrime);
}