trecadecaphobia 

irrational fear of the number 13.

He suffers from trecadecaphobia, it makes no sense.

trecadecaphobia by tjgirl February 11, 2009

triscadecaphobia

The fear of number 13

Being afraid of the 13th of the month is an example of triscadecaphobia

triscadecaphobia by Pure_evul February 11, 2008