Problem Statement

To generate a sequence of n-digit pseudorandom numbers, an n-digit starting value is created and squared, producing a 2n-digit number. If the result has fewer than 2n digits, leading zeroes are added to compensate. The middle n digits of the result would be the next number in the sequence and returned as the result. This process is then repeated to generate more numbers. numbers (6 digits) as shown above.

Let's start with the solution:

main :: [sys_message]
main = [Stdout (lay (map show numbers))]
       where numbers = take 5 (randoms 6 seed)
             seed    = 675248

randoms :: num->num->[num]
randoms sz = tl . iterate (msq sz)

msq :: num->num->num
msq sz seed = sq div (10^(sz div 2)) mod 10^sz
              where sq = seed^2