@% = &2040A
      MAX_N = 20
      TIMES = 1000000

      FOR n = 1 TO MAX_N
        avg = FNtest(n, TIMES)
        theory = FNanalytical(n)
        diff = (avg / theory - 1) * 100
        PRINT STR$(n), avg, theory, diff "%"
      NEXT
      END

      DEF FNanalytical(n)
      LOCAL i, s
      FOR i = 1 TO n
        s += FNfactorial(n) / n^i / FNfactorial(n-i)
      NEXT
      = s

      DEF FNtest(n, times)
      LOCAL i, b, c, x
      FOR i = 1 TO times
        x = 1 : b = 0
        WHILE (b AND x) = 0
          c += 1
          b OR= x
          x = 1 << (RND(n) - 1)
        ENDWHILE
      NEXT
      = c / times

      DEF FNfactorial(n)
      IF n=1 OR n=0 THEN =1 ELSE = n * FNfactorial(n-1)