without delegate

private static long Ylee(long N)
        {
            long count = 0; // verifiy valid (n,k) as sigma(n+k) - sigma(n) = sigma(k) + n*k

            for (Int64 i = Convert.ToInt64(Math.Sqrt(2 * N)); i > 1; i--)

                if ((N - ((i * (i + 1)) / 2)) % i == 0) count++;

            return count;
        }