Studs 16 inches on center, but extra one between two of the studs with electrical outlet?
I never waste a stud for a receptacle. You may commonly find extra studs in on or close to corners or where walls join but To put a stud in for a receptacle unlikely, receptacles have spacing requirements 12’ between them or no point more than 6’ from a receptacle with continual walls (no door ways etc). But there is no minimum spacing they can be next to each other.