The Best (and Worst) Ways to Shuffle Cards - Numberphile
Why Hacker News recommends it
HN points to it as a good, anecdote-filled introduction to the math of shuffling from the expert himself.
What it is
Persi Diaconis explains on Numberphile the mathematics of card shuffling, including why seven riffle shuffles are needed to randomize a deck and how different shuffles compare.
Recommended by 3 HN commenters across 3 different months, 2015 to 2026.
What Hacker News said
Recommends shuriu · 2015-07 · on “The Coin Flip: A Fundamentally Unfair Proposition? (2009)”
This video from Numberphile goes in depth about this: [LINK] . The guy talking, is Persi Diaconis, is the main author of the paper this article is based upon. He also has done research on the randomness of shuffling cards: [this video] . Pretty cool stuff!
Recommends evanb · 2018-06 · on “The Math of Card Shuffling”
There's a great numberphile with Persi Diaconis all about shuffling: [this video] The extra footage is fantastic, too.
Recommends fisian · 2026-06 · on “Seven Perfect Shuffles Randomize a Deck of Cards. But How Many Sloppy Ones?”
Numberphile has a video with Persi Diaconis about the seven perfect shuffles. It gives a lot of insight and anectdotes in addition to the central theorem: [this video]
Cites trcollinson · 2021-02 · on “The mathematics of shuffling”
One of my absolute favorite mathematicians is Persi Diaconis who is mentioned in this paper and was the original basis for this area of research. Well worth learning about. He was a runaway. Then a magician, trained by Dai Vernon and worked along side people like the late Ricky Jay and Richard Turner. He went on to get PhD from Harvard and got a MacArthur Fellowship. He is a legend. Ricky Jay talking about his childhood friend Persi: [LINK] Persi on Numberphile: [this video] A great lecture: [LINK]