{%- set addrs = [addr + ':4161' for addr in ['1', '2', '3']] %}

debug:
    test.show_notification:
        - name: Debug Information
        - text: |
            {{ addrs }}

Output:
---

root@4994eb15e8e5:/srv/salt# salt '*' state.apply debug
salt-minion:
    Data failed to compile:
----------
    Rendering SLS 'base:debug' failed: Jinja syntax error: expected token ',', got 'for'; line 1

---
{%- set addrs = [addr + ':4161' for addr in ['1', '2', '3']] %}    <======================

debug:
    test.show_notification:
        - name: Debug Information
        - text: |
[...]
---
ERROR: Minions returned with non-zero exit code