2012 is an interesting year for Friday the 13th occurances. There are three of them this year and they are 13 weeks a part. The folks suffering from the phobia of this supposedly unlucky combination of week day and date of month are called paraskevidekatriaphobics. One famous person who had this fear was President Franklin D. Roosevelt. Thomas Fernsler, a University of Delaware mathematician studing the number 13, noted that the president refused to take a train trip on that unlucky day.
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