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David Radcliffe
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David Radcliffe

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I wrote a little JavaScript application to play the game of Nim. Enjoy! http://convex.org/nim/
The Game of Nim. Set up the board by clicking on the gray squares. Click on the Move button when you are ready to play. Then you and the computer will take turns removing the blue boxes. Clicking on a blue box will remove that box, and all boxes directly above it. The player that removes the ...
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David Radcliffe

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The Franklin graph shows the connections between the 12 different ways to express a+b+c. Each edge represents an application of the commutative or transitive law. Was this known previously?
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Wow, very interesting!
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Do the frequencies of Emoji characters follow Zipf's law?
Emojitracker.com is a very interesting site that tracks how often each emoji is used on Twitter. The statistics are updated in real time, and it's really quite amazing to watch. (In case the reader...
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I am investigating the sum of digits of 2^n. I have discovered an elementary proof that s(2^n) > log_4 n for all n. What is the best known lower bound for this sequence?
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Ah. In that case, I have discovered an elementary proof that s(2^n) is bounded.
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This is a directed graph with 1000 vertices, numbered from 0 to 999, and a directed edge from vertex n to vertex (n*n+2) mod 1000 for each n. I think it's rather pretty.
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great work thank you david
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Have him in circles
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David Radcliffe

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I thought I'd share my results on a fun math problem. Suppose that an infection spreads among the squares of a checkerboard in such a manner that a square with three infected neighbors becomes infected itself. What is the smallest number of squares that must be infected initially for the infection to spread to the entire board?
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David Radcliffe

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Interactive visual proof that every pentagonal number is 1/3 of a triangular number.
Triangular and pentagonal numbers. This applet illustrates the theorem that every pentagonal number is one-third of a triangular number. Drag the slider to change the size of the triangle. N = 8.
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I wrote a blog post discussing a question of Kurt Mahler: Which squares have only the digits 0 or 1 when written in base 5? I found all such squares less than 5^64 and proved that infinitely many are not divisible by 5.
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Definitely not.
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Have him in circles
481 people
Bruno Reddy's profile photo
Bill Bushey's profile photo
Darryl Dañez's profile photo
Emily Jessica's profile photo
Tony Alteparmakian's profile photo
Chris Ludwig's profile photo
K12 School Supplies's profile photo
Laurent Bartholdi's profile photo
Stephanie Elsen's profile photo
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I am a college math instructor living in St. Paul MN. I am not a vice president at Google; that is a different David Radcliffe. I did not star in the Harry Potter movies; that is Daniel Radcliffe.
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