BuildMultiplicationTable returned null

using System;

namespace Treehouse.CodeChallenges
{
    public static class MathHelpers
    {
        public static int[][] BuildMultiplicationTable(int maxFactor)
        {
            int[][] table = new int[maxFactor + 1][];
            for (int i = 0; i < maxFactor; i++)
            {
                table[i] = new int[maxFactor + 1];

                for (int j = 0; j < maxFactor; j++)
                {
                    table[i][j] = i * j;
                }
            }

            for (int i = 0; i < maxFactor; i++)
            {
                for (int j = 0; j < maxFactor; j++)
                {
                    Console.Write(table[i][j]);
                }
                Console.WriteLine();
            }
            return table;



        }
    }
}