600000 eratosthenes

  [ dup sqrt
    tuck dup * = ]                is exactsqrt ( n --> n b )

  [ dup isprime iff
      [ drop false ] done
    dup 4 mod 1 != iff
      [ drop false ] done
    dup exactsqrt iff
      [ 2drop false ] done
    temp put
    3 from
      [ 4 incr
        index temp share > iff
          [ drop false end ]
          done
        index isprime not if done
        dup index /mod 0 != iff
          drop done
        isprime not if done
        drop index end ]
    temp release ]                is blum      ( n --> n   )

  [ dup blum
    over echo
    say " = "
    dup echo
    say " * "
    / echo cr ]                   is echoblum   ( n -->     )

  say "The First 50 Blum integers:"
  cr cr
  [] 1 from
     [ 4 incr
       index blum if
         [ index join ]
       dup size 50 = if end ]
  witheach echoblum
  cr
  say "The 26828th Blum integer:"
  cr cr
  0 1 from
    [ 4 incr
      index blum if 1+
      dup 26828 = if
        [ drop index end ] ]
  echoblum