Generating a number

Hi folks

Can anyone help me to generate number as specified below.

I want my number to get generated as a combination of region code & and a sequence number which depends on the person cat type

ex

If cat type - I (1000-2000)..i.e the number generating here will start with 1000,1001....and this number has to get concatenated with regoin code while syndicating.........i.e if the person belongs to AP.then the number should be as AP1000.

Is this possible?