You Do Need power plug adapter while traveling from Oman to Côte d'Ivoire (Ivory Coast).

Here is Why You Need An Adapter

The outlet and plug type used in Côte d'Ivoire (Ivory Coast) are C and E and in Oman is G. This is how they look like.

Oman

In Oman, outlets of type G are in use.

Type G

Côte d'Ivoire (Ivory Coast)

In Côte d'Ivoire (Ivory Coast), outlets of type C and E are in use.

Type C

Type E