1=1!
2=2!
145=1!+4!+5!
40585=4!+0!+5!+8!+5!
These are the only numbers with this property.
[Poole, 1971]

Sometimes, I wonder if I wrote Euler's Gem (book about Euler's poly. formula/Euler characteristic) as penance for stumbling on this question during my oral exam in grad school.
'How do you know that surface is a torus with a disk removed?'
Ans: EC=-1, orientable, one boundary

A few action shots of my tiling theory students' poster presentation. Ten students, five poster topics:
• Marjorie Rice's pentagon tilings
• Tiling the hyperbolic plane
• Wallpaper patterns at the Alhambra
• Polyominoes
• Uniform tilings with star polygons

A couple of my tiling theory students recreated this 1907 puzzle by Henry Dudeney. The objective is to reassemble these 12 pentominos and one tetromino into an 8x8 chess board. Original: gutenberg.org/files/27635/27…

Colleague: 'Every time I walk by your hat tile display, I see Ukraine.'

One of the math limericks at Futility Closet futilitycloset.com/2017/04/29/mat…

To my ears:

'years of age' : 'years old' :: 'utilize' : 'use'

Interesting n-gram for the last 100 years

I play sumplete.com, the game 'ChatGPT made' (copied existing games), just about every day. The surprising thing is how much faster I am now at adding single-digit numbers. I didn't think I added slowly before, but now I can just scan across and get the sum. #practice

I am excited to be going to MathFest this summer, and I’m honored to be giving the Martin Gardner lecture. I hope to see you all there!

What is the meaning behind this square root of 36 sticker? (Serious question.)

washingtonpost.com/world/2024/04/…

Happy 247th birthday to Carl F. Gauss. Here's the 2018 Google Doodle doodles.google/doodle/johann-…

I made some wooden Penrose kites and darts.

Mathematician Chris Staecker (Chris Staecker) gives a very interesting analysis of a recount of a ranked-choice election in Alaska. youtube.com/watch?v=TfwQkF…