Serial.hs

import Control.Monad
import Test.QuickCheck
import Test.QuickCheck.Gen
import System.Random
import System

data Serial = Serial String Int

instance Show Serial where
  show (Serial prefix number) = prefix ++ show number

instance Arbitrary Serial where
  arbitrary = do
    prefix <- vectorOf 3 $ elements ['A'..'Z']
    number <- choose (10000, 99999)
    return $ Serial prefix number

serialGen :: Int -> [Serial]
serialGen seed = unGen arbitrary (mkStdGen seed) 9999999

main = do
  args <- getArgs
  case map read args of
    []        -> putStrLn "serial <number of serials> [seed]"
    [n]       -> go n 2
    [n, seed] -> go n seed
  where 
    go n seed = mapM_ print (take n $ serialGen seed)