| Title | Test
                    Find
                    
                    Pattern Title | 
            
                | Expression | ^([51|52|53|54|55]{2})([0-9]{14})$ | 
            
                | Description | Validate against any mastercard number. All MC's start with a number between 51 and 55 and are followed by 14 other numbers. | 
            
                | Matches | 5125632154125412 | 5225632154125412 | 5525632154125412 | 
            
                | Non-Matches | 5625632154125412 | 4825632154125412 | 6011632154125412 | 
            
                | Author | Rating:  Jeff Johns | 
            
                | Source |  | 
            
              | Your Rating |  | 
        
    
 
    
    
     
        
                
	                Title: Yell's code
	                Name: Nate
	                Date: 4/18/2008 3:42:32 PM
	                Comment: 
My apologies Yell, your code does work, the fault was mine with having a whitespace I did not notice at the end (and I didn't notice that yours does check for an end of string).
                
                
            
                
	                Title: Yell's code
	                Name: Nate
	                Date: 4/17/2008 4:41:55 PM
	                Comment: 
Yell, your code fails to pass the valid card
5199999999999999
                
                
            
                
	                Title: False Positive
	                Name: Nate
	                Date: 4/17/2008 4:26:14 PM
	                Comment: 
It appears to match anything that contains 2 of the numbers listed. So it matches 15, 24, 35, 31, 43 and so on, so long as both of the numbers appear at least once in 51|52|53|54|55.
                
                
            
                
	                Title: This is a better one
	                Name: YeLL
	                Date: 3/2/2008 7:53:17 AM
	                Comment: 
^5[1-5][0-9]{14}$
                
                
            
                
	                Title: False Positive
	                Name: Paul
	                Date: 6/28/2005 4:04:21 PM
	                Comment: 
Why does this match ?
1599999999999999