Triskaidekaphobia

Triskaidekaphobia is the fear of the number thirteen. The number 13 has been linked to bad luck in the western superstition. Some buildings in the United States do not have a "13th floor."
The term was first used by Isador Coriat in "Abnormal Psychology".
There is also a fear of Friday the 13th. This fear is called "paraskevidekatriaphobia" or "friggatriskaidekaphobia".