[ale] Regex question

[Chris Fowler]

I need to do a match using perl regex.  Here is the possible strings
that will be in a stream:

XMI
XMI001
XMI002
XMI###

Were the '#' could be any number.  I need to be able to detect that
the above pattern matches in a chunk of data.  What is the correct
regex that will fit that pattern?

Thanks,
Chris