What is the index at the beginning of oracle BIN$?

Did you find it when you checked the index? If so, it should be the related index of the deleted table or the deleted index.

The table at the beginning of BIN$ is basically the most common table in the recycle bin after drop table without purge.

The elimination method is to empty the recycle bin, and the execution is to clear the recycle bin.

Another possibility is the default index, which I forgot (anyway, the naming rules of the system are followed by a bunch of numbers, and I really can't remember what is in front), which is the primary key directly established when the table is established (that is, the primary key directly established when the table is established, which is unique). In fact, this kind of index will also have a named index (only this kind of index is directly named by the system and does not follow our own naming rules).