NullReferenceException: Object reference not set to an instance of an object

Hello,

I have 16 gameobjects using the same script MotionDetector and each store in the private int "k" the number each object is clicked.

I also have this script

using UnityEngine; using System.Collections;

public class SodokuPuzzle : MonoBehaviour {

MotionDetector[] myObjects;

void Start() {

     myObjects = new MotionDetector[16]; // new array with 16 elements ( 0..15 )
 for (int i = 0; i <= 15; i++)
 {
     GameObject go = GameObject.Find("B"+ (i+1));
     if (go != null)
         { Debug.Log("got : "+i);
             myObjects[i] = go.GetComponent<MotionDetector>();
         }
     else
         Debug.Log("sommething if wrong");
     }
      

}

 // Update is called once per frame
 void Update () {
 

 
     if(myObjects[0].k+myObjects[1].k+myObjects[2].k+myObjects[3].k==10) //Check first rows sum is 10
     {Debug.Log("first row corect");
 
     }
     else
     {    
     Debug.Log("first row not corect");
     }
     
 
     
 if(myObjects[4].k + myObjects[5].k + myObjects[6].k +myObjects[7].k==10) //Check second rows sum is 10
     {Debug.Log("Second  row corect");
     g++;
     }
     else
     {    
     Debug.Log("second row not corect");
     }
     
     if(myObjects[8].k + myObjects[9].k + myObjects[10].k +myObjects[11].k==10) //Check third rows sum is 10
     {Debug.Log("Third  row corect");
     g++;
     }
     else
     {    
     Debug.Log("Third  row not corect");
     }
              
     
         
 }
 
 

}

It comes up with the error: NullReferenceException: Object reference not set to an instance of an object SodokuPuzzle.Update () (at Assets/SodokuPuzzle.cs:65)

If I delete 2 out of the 3 if statements (in the update function) it works fine. Why would it work for 1 IF statement and not 2 or 3? Please help.