UD’s Dr. 13, also known as Professor Thomas Fernsler has spent more than 20 years investigating and speaking publicly about this one number that’s the focus of so much superstition. He is available for interview to discuss the statistics behind the superstitions, its history and why it’s considered unlucky.

We won't see another year like 2015 again, with 3 Friday the 13th in one calendar year, until 2026. In fact, a year like 2015 with a triple set of Fridays falling on the 13th typically only comes around only once every 11 years. And yet, the 13th day of the month is more likely to fall on a Friday than any other day of the week.

Some consider the day spooky, others silly, and for horror film fans it’s superb - not only is the number 13 often considered unlucky, but Friday also has a reputation as a day of bad luck. It was the day Christ was crucified and historically has been the day reserved for capital executions.

Meanwhile, separate from the day of the week, the number 13 has a reputation all its own. Napoleon, J. Paul Getty, Herbert Hoover and Franklin D. Roosevelt all feared the number 13 – a condition called triskaidekaphobia.

Facts about 13

1. The number suffers from its position after 12, which numerologists consider a complete number, encompassing the number of months in a year, signs of the zodiac, gods of Olympus, labors of Hercules, tribes of Israel, apostles of Jesus, days of Christmas and eggs in a dozen.

2. The first person to die in a car accident was killed in New York City on Sept. 13, 1899.

3. The British Navy is notoriously afraid of Friday the 13th. Nonetheless, it built a ship named Friday the 13th. On its maiden voyage, the vessel left dock on a Friday the 13th and was never heard from again.

4. The ill-fated Apollo 13 launched at 13:13 CST on 4/11/70. The sum of the date’s digits is 13. The explosion that crippled the spacecraft occurred on April 13.

5. Many hospitals have no room 13. Some tall buildings have no 13th floor. The numbers on the rooms and elevators jump from 12 to 14.

6. Quarterback Dan Marino wore No. 13 throughout his career with the Miami Dolphins. Marino is said to be the best quarterback who never won a Super Bowl.

7. Butch Cassidy was born on Friday, April 13, 1866.

8. President Franklin D. Roosevelt would not travel on the 13th day of any month and would never host 13 guests at a meal.

9. Superstitious diners in Paris can hire a quatorzieme, or professional 14th guest.

10. Woodrow Wilson considered 13 his lucky number, but he may have been wrong. The first sitting president to leave the country, Wilson arrived in Normandy, France, on Friday, Dec. 13, 1918. He returned from Europe with a treaty he couldn’t get Congress to sign. He toured the U.S. to rally support for the treaty and, while traveling, suffered a near-fatal stroke.

11. The seals on the back of a dollar bill include 13 steps on the pyramid, 13 stars above the eagle’s head, 13 war arrows in the eagle’s claw and 13 leaves on the olive branch.

12. Fidel Castro was born on Friday, Aug. 13, 1926.

13. Mark Twain once was the 13th guest at a dinner party. A friend warned him not to go. “It was bad luck,” Twain later told the friend. “They only had food for 12.”Contact [email protected] to arrange an interview with Dr. 13