F isPrime(n)
   I n < 2
      R 0B
   L(i) 2 .. n
      I i * i <= n & n % i == 0
         R 0B
   R 1B

F mobius(n)
   I n == 1
      R 1

   V p = 0
   L(i) 1 .. n
      I n % i == 0 & isPrime(i)
         I n % (i * i) == 0
            R 0
         E
            p = p + 1

   I p % 2 != 0
      R -1
   E
      R 1

print(‘Mobius numbers from 1..99:’)

L(i) 1..99
   print(f:‘{mobius(i):4}’, end' ‘’)

   I i % 20 == 0
      print()