Get entries that's not already listed
This is how you're getting your "Forside" articles:

{% for entry in entry.artikkelbolk1.limit(14) %}
    &lt;!--print out article content--&gt;
{% endfor %}


this let me assume you're using an entries field to "collect" articles from your "artikkelbolk1" section.
The Twig syntax you're using is actually a shortcut for this:

{% for entry in craft.entries({
    relatedTo: { sourceElement: entry, field: 'artikkelbolk1' },
    order:     'sortOrder',
    limit:     14
}) %}
    &lt;!--print out article content--&gt;
{% endfor %}


So it get's you all entries related to your current entry, the preset entry model of your "forside" section.

To get all articles not listed on "Forside" you'd do this. First, grab those "forside" entries again, but you're only interested in the IDs
of the entry models, that's why you now append the ids() method. Then join the IDs into a string with the following syntax (use Twig's join filter for that!):

'and, not 42, not 82, not 20'


So it basically lists all entry IDs prefixed with 'not'; the 'and' at the beginning just makes Craft aware that you're listing multiple values. With this string you can now go ahead and exclude your entries from an ElementCriteriaModel. To do that simply pass the string into the id parameter.

{% set forside = craft.entries.section('forside').first() %}

{% set forsideEntriesIds = craft.entries({
    relatedTo: { sourceElement: forside, field: 'artikkelbolk1' },
    order:     'dateCreated desc',
    limit:     14
}).ids() %}

{% set idParam = 'and, not ' ~ forsideEntriesIds|join(', not ') %}

{% for entry in craft.entries.section('artikkel').id(idParam).order('dateCreated desc') %}
    &lt;!--print out article content--&gt;
{% endfor %}