I couldn't have the number 13 hangin' around, so I now have 14 Septimius Severus coins (purchased from the same dealer as the last few I posted). This one happens to be a provincial from Nikopolis ad Istrum, a Roman town founded by Emperor Trajan around 101-106 AD.

AE17 Assarion Moushmov 927
OBV: AV K L CEVHPOC, laureate bust right
REV: NIKOPOL PROC IC, Draped bust of Serapis in modius, facing right
2.6g, 15mm