public static double HashCore(int[] array)
    {
        ulong adler = 1L;
        ulong s1, s2;

        for (int i = 0; i < array.Length; i++)
        {
            s1 = adler & 0xffff;
            s2 = (adler >> 16) & 0xffff;
            s1 = (s1 + (ushort)array[i]) % 65521;
            s2 = (s2 + s1) % 65521;
            adler = (s2 << 16) + s1;
        }

        return (double)adler;
    }