C#: Euler 46

EulerLEVEL2XXDD

Goldbach’s other conjecture

https://projecteuler.net/problem=46
It was proposed by Christian Goldbach that every odd composite number can be written as the sum of a prime and twice a square.

static void Main(string[] args)
{
    Console.BufferHeight = 8000;
    Console.WriteLine("Goldbach's other conjecture");
 
    for (int n = 3; n < 100000; n+=2)
    {
        if ( !isPrime(n) )
        {
            Console.WriteLine(n);
            bool works = false;
            while (!works)
            {
                for (int abc = 1; abc < 50; abc++)
                {
                    for (int j = 0; j < 10000; j++)
                    {
                        if (isPrime(j))
                        {
                            double check = j + (2 * Math.Pow(abc, 2));
                            if ((j + 2 * Math.Pow(abc,2)) > n)
                                break;
                            if (n == check)
                            {
//Console.WriteLine(n + " = " + j + " + 2*" + abc + "^2");
                                works = true;
                            }
                            if (works)
                                break;
                        }
                    }
                }
            }
            Console.WriteLine("----");
        }
    }
}
 
public static bool isPrime(int n)
{
    if (n == 1)
        return false;
    if (n == 2)
        return true;
    for (int i = 2; i < n; ++i)
    {
        if ((n % i) == 0)
            return false;
    }
    return true;
}

output
output

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