...
There are the following parameters:
- User primers - the pair of forward and reverse primers user can check on the absence of unwanted connections (like hairpins, self- and hetero-dimers).
- Choose generated sequences as user primer's end - user primers could be extended with the 8-bases sequences on 5' and 3' ends. These sequences do not form too simple unwanted connections (for example, "AAAATTTT", obviously, has a hairpin).
Forward primer - forward primer.
...