What have I done wrong ? I am getting "Object reference not set to an instance of an object" error

namespace Treehouse.CodeChallenges
{
    public static class MathHelpers
    {
        public static int[][] BuildMultiplicationTable(int maxFactor)
        {
            int[][] Multiplication = new int[maxFactor + 1][];
            for(int index = 0; index < Multiplication.Length; index++)
            {
               if (index == 0)
               {
                 for(int value = 0; value < Multiplication[index].Length; value++)
                 {
                    Multiplication[index][value] = 0;  
                 }
               }
               else if(index == 1)
               {
                   for(int value = 0; value < Multiplication[index].Length; value++)
                   {
                     Multiplication[index][value] = value;   
                   }
               }    
               else
               {
                 for(int value = 0; value < Multiplication[index].Length; value++)
                 {
                     if (value == 0)
                     {
                         Multiplication[index][value] = 0;
                     }
                     else if (value == 1)
                     {
                         Multiplication[index][value] = value;
                     }
                     else
                     {
                         Multiplication[index][value] = value * Multiplication[1][value];
                     } 
                 }   
               }
              }
            return Multiplication;
        }

    }
}