title: postgres : create a sequence like 0000001 to 00000n
body: <p>Dear All,<br>
  I want to create a sequence in postgres which is like 0000000001 to 00nnnnnnnnn 
  
  normally we can create from 1 to n , but I want that to be preceeded with 0's<br/>
  Is there any easy way to do this ??? 
  </p>