Happy Square Day! It’s quite rare for the numbers of the date to all be perfect squares, and even rarer for them to be consecutive!
April, 2016 has been a fun month for mathematical dates! So far this month we’ve had 4/2/16 (an Exponent Day), 4/4/16, and 4/8/16 (a Geometric Mean Day, or alternately, a Powers of 2 Day). And there are more fun mathematical dates to come!
Today we celebrate the second Permutation Day of the year! I call days like today permutation days because the digits of the day and the month can be rearranged to form the year.
We can also consider today a Transposition Day, as we need only a single transposition (an exchange of two numbers) to turn the year into the day and date.
Celebrate Permutation Day by mixing things up! Try doing things in a different order today. Just remember, for some operations, order definitely matters!
Today we celebrate the first Permutation Day of the year! I call days like today permutation days because the digits of the day and the month can be rearranged to form the year.
Celebrate Permutation Day by mixing things up! Try doing things in a different order today. Just remember, for some operations, order definitely matters!
In honor of the new year, here’s the complete graph on 64 vertices, with its 2016 edges!
A complete graph is a graph in which every pair of vertices is connected with an edge. In a complete graph with n vertices, there are
edges. The above graph has 64 vertices equally spaced around the perimeter. Thus, 
edges.
The number 2016 is special for a variety of reasons. For example,
So 2016 is equal to the sum of the first 63 positive integers! This makes 2016 a triangular number, a fact beautifully demonstrated by David Swart in this image.
And John D. Cook illustrates the combinatorial nature of 2016 by pointing out that this is the number of ways to place two pawns on a chessboard!
However you think of it, 2016 is a pretty great number! And here’s hoping 2016 is a great year.
Today we celebrate the final Permutation Day of the year! I call days like today permutation days because the digits of the day and the month can be rearranged to form the year.
Celebrate Permutation Day by mixing things up! Try doing things in a different order today. Just remember, for some operations, order definitely matters!
