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The Number of the Day: 13

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Friggatriskaidekaphobia (or paraskevidekatriaphobia) is the name for the fear of Friday the 13th. That’s not to be confused with the fear of the number 13 – which is known as triskaidekaphobia.


Related Fact: The original Friday the 13th film was made for only $550,000 and earned more than $39 Million in the United States alone.


[Source: Psych Central, Merriam-Webster and IMDB. See previous Numbers of the Day here. ]

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This Puzzling Math Brain Teaser Has a Simple Solution
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Fans of number-based brainteasers might find themselves pleasantly stumped by the following question, posed by TED-Ed’s Alex Gendler: Which sequence of integers comes next?

1, 11, 21, 1211, 111221, ?

Mathematicians may recognize this pattern as a specific type of number sequence—called a “look-and-say sequence"—that yields a distinct pattern. As for those who aren't number enthusiasts, they should try reading the numbers they see aloud (so that 1 becomes "one one," 11 is "two ones," 21 is "one two, one one,” and so on) to figure the answer.

Still can’t crack the code? Learn the surprisingly simple secret to solving the sequence by watching the video below.

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What Number Is The Answer?
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