jsiehler @jsiehler@mathstodon.xyz

Current best candidate:
https://scott-ammon.github.io/nim/index.html#!

Recommendations for the best browser-based game of Nim that my students could play? I used to use the very slick "Pearls Before Swine" implementation, but I'm looking for something that avoids Flash (but doesn't look like total crud, either).

One wonders why, exactly, this redirect page exists:

https://en.wikipedia.org/w/index.php?title=Floopy_disk&redirect=no

Schwarz-Rot-Gelb

A problem of mine appeared in the lastest Mathematics Magazine:
Suppose \(\pi\) is a permutation of \(\{1,2,\ldots,2m\}\). Consider the (possibly empty) subsequence of \(\pi(m+1),\pi(m+2),\ldots,\pi(2m)\) consisting of only those values which exceed \(\max\{\pi(1),\ldots,\pi(m)\}\).

Let \(P(m)\) denote the probability that this subsequence never decreases, when \(\pi\) is a randomly chosen permutation of \(\{1,2,\ldots,2m\}\). Evaluate the limit of \(P(m)\) as \(m\to\infty\).

Black and white.

Every time I unwittingly click on a researchgate link in the search results and get a "We've picked up some unusual traffic from your network and have temporarily blocked access from your IP address" message, I wonder who decided that this blatant lie was the best way to make a good first impression. Hey, this doesn't seem scammy at all, sign me up!

Knotty!

These new journals are getting rather niche lately, it seems.

An enjoyable problem (104.B) from the latest Mathematical Gazette: A regular 7-gon is inscribed in the unit circle, with one vertex at (1,0). Find the equations of the two parabolas, symmetric across the x-axis, which pass through the vertices of the heptagon as shown.

"Two Sines in the Sunset"

This graphic may be too obscure to interpret, but it is based on a lovely fact that I just learned and have been boring people with for days now. Charming little paper here:
http://shorturl.at/berZ2
(link goes directly to a PDF)

Pair up!

\(30561_7 = 16503_8\)

Whirl.

Interleave the words to make a common nine-letter word, with the letters of the given words appearing in order. For example:
(chat, racer) \(\to\) CHAracTer,
or
(rely, dives) \(\to\) diveRsELY.

1. (tram, stage)
2. (dirt, super)
3. (brig, lumen)
4. (sped, tamed)
5. (race, heath)
6. (rent, sting)
7. (race, seven)

Square!

For optimum enjoyment, you should imagine Parry Gripp singing "Inchworm on a Pentagon."

All I can come up with for an animation today is this little inchworm guy.

Pledge: Before I die, I will settle on a satisfactory notation to teach the general case of the Inclusion/Exclusion Principle.