[ 0 swap dup times
      [ i over gcd
        1 = rot + swap ]
      drop ]                is totient    (   n --> n )

  [ 0 temp put
    times
      [ i dup 1+ totient
        = temp tally ]
     temp take ]            is primecount (   n --> n )

  25 times
     [ say "The totient of "
       i^ 1+ dup echo
       say " is "
       dup totient dup echo
       say ", so it is "
       1+ != if say "not "
       say "prime." cr ]
  cr
  ' [ 100 1000 10000 100000 ]
  witheach
    [ say "There are "
      dup primecount echo
      say " primes up to " echo
      say "." cr ]