public static long SumOfPrimes(int n)
{
var primes = OptimusPrime.Primes(n);
long sum = primes.Sum();
return(sum);
}
public static long Solve(int minDivisors)
{
// for help: the formula for a Triangular Number is x_n = n(n+1)/2
// https://www.mathsisfun.com/algebra/triangular-numbers.html
//http://www.mathblog.dk/triangle-number-with-more-than-500-divisors/
var provenPrimes = OptimusPrime.Primes(500000).ToArray();
long max = (long)Int32.MaxValue + 100;
var triangles = TriangleNumberGenerator(0, max);
foreach (long tri in triangles)
{
int divisors = FactorizationNumDivisors(tri, provenPrimes);
if (divisors > minDivisors)
{
return(tri);
}
}
return(0);
}
