This is a Tiberius Denarius of the so-called "Tribute Penny" type - reverse is Livia (his mother, the presumed poisoner of many of the Julio-Claudians) seated right. This was virtually the only type of denarius issued by Tiberius over his long reign from 14-37 AD. You have had at least one specimen of this type before, about which I wrote at some length if I recall correctly, so I would refer you to my earlier description and explanation of the type.
Mark