public static int truncatableprimes(int n)
{
int count = 0;
int sum = 0;
PrimeFunctions.GeneratePrimesToList(1000000);
PrimeFunctions.ConvertToHash();
int i = 4;
while (count < n)
{
bool isprime = true;
List <int> trunc = CombinatoricFunctions.truncations(PrimeFunctions.PrimeList[i]);
foreach (int truncation in trunc)
{
if (!PrimeFunctions.PrimeListHash.Contains(truncation))
{
isprime = false;
break;
}
}
if (isprime)
{
count++;
sum += PrimeFunctions.PrimeList[i];
}
i++;
}
return(sum);
}
public static long PandigitalMultiples(long n)
{
long maxpandigital = 1;
for (int i = 1; i < n; i++)
{
long mult = i;
int k = 2;
while (mult < 1000000000)
{
mult = CombinatoricFunctions.concatenatenum(mult, k * i);
if (mult > 100000000 && mult < 1000000000)
{
if (MiscFunctions.IsPandigital((int)mult))
{
if (mult > maxpandigital)
{
maxpandigital = mult;
}
}
}
k++;
}
}
return(maxpandigital);
}
public static int CirculuarPrimes(int n)
{
PrimeFunctions.GeneratePrimesTillNToList(1000000);
PrimeFunctions.ConvertToHash();
int count = 0;
for (int i = 2; i < n; i++)
{
List <int> rots = CombinatoricFunctions.rotations(i);
bool prime = true;
foreach (int rot in rots)
{
if (!PrimeFunctions.PrimeListHash.Contains(rot))
{
prime = false;
break;
}
}
if (prime)
{
count++;
//Console.WriteLine(i);
}
}
return(count);
}
public static int DoubleBasePalindromes(int n)
{
int sum = 0;
for (int i = 1; i < n; i++)
{
string binary = Convert.ToString(i, 2);
if (CombinatoricFunctions.IsPalindrome(i) && CombinatoricFunctions.IsPalindrome(binary))
{
sum += i;
}
}
return(sum);
}
public static int DigitFactorials(int n)
{
int sum = 0;
CombinatoricFunctions.generatefactorial(10);
for (int i = 3; i < n; i++)
{
int[] digits = MiscFunctions.DigitsFromInt(i);
BigInteger tempsum = 0;
foreach (int digit in digits)
{
tempsum += CombinatoricFunctions.factorial(digit);
}
if (tempsum == i)
{
sum += i;
}
}
return(sum);
}
public static int LargestPalindromeProduct(int n)
{
int largest = 0;
//Loop through every combination of numbers until n
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
//If i*j is a palindrome then check if it's largest then the largest so far and set it to an int
if (CombinatoricFunctions.IsPalindrome(i * j))
{
if ((i * j) > largest)
{
largest = i * j;
}
}
}
}
return(largest);
}
public static int FactorialDigitSum(int n)
{
return(MiscFunctions.SumOfDigits(CombinatoricFunctions.factorial(n)));
}
public static string LatticePathsFast(int n)
{
return(CombinatoricFunctions.binomialcoeff(2 * n, n).ToString());
}