So, there is a hexagonal grid made up of 19 circles (see attached image).  The objective is to arrange the numbers 1 to 19 on the circles so that, in any direction of the lines, the sum of the numbers is the same.  Problem is, I'm having trouble figuring out what the sum should be - anyone know how I would go about determining this sum?
                
                    
                        
                            
                        
                    
                
                
                    the idiot is the person who follows the idiot and your not following me your insulting me your following the path of a idiot so that makes you the idiot - LC Tusken
                
            