Regular Expression for Wright Express?

There is plenty of info available about regular expressions for credit card numbers (for example http://www.regular-expressions.info/creditcard.html). However I have not been able to find info on the regular expression (or any other description) for the number used by Wright Express (which I think is some kind of fuel card). 开发者_开发问答Does anyone know what it is?

Based on their examples on their website, such a number looks like 0400 00 123456 7. To check this format with a regular expression, you could use

"\d{4} \d{2} \d{6} \d"