A Great Day for a Pattern
November 12, 2021 at 12:01 pm 3 comments
When I first saw today’s date in mm/dd/yy format — 11/12/21 — I thought, “Well, that’s pretty cool. It’s all 1s and 2s.” And then I thought, as I’m sure you did, “In ternary, that’d be 376,” because everyone thinks in ternary, right?
But then I looked at the number again, and I thought, “Ah, hello, old friend. Good to see you again.”
Those six digits form the fifth term of a famous pattern:
1
11
21
1211
111221
So your first question is, what’s the next term?
If you’ve never seen this pattern before, it’s worth a little of your time to try to figure it out before reading more about it at MathWorld.
Your second question — if you’re still reading — is, what’s the greatest digit that will ever appear in this sequence? As you can see above, the first five terms only contain 1s and 2s. What digits are in the sixth term? What digits will appear beyond the sixth term? How do you know?
Entry filed under: Uncategorized. Tags: date, number, pattern.
1.
Mary | November 12, 2021 at 12:09 pm
Should the second number from the right be a 2?
2.
venneblock | November 12, 2021 at 12:47 pm
Great catch, Mary! It’s been fixed.
3.
chrissmith180954163 | November 12, 2021 at 12:19 pm
Patrick,
I couldn’t resist exploring that wee sequence recently either! https://www.youtube.com/watch?v=yFFY6YQCwzA&t=6s
Thanks!
Chris
On Fri, Nov 12, 2021 at 5:04 PM Math Jokes 4 Mathy Folks wrote:
> venneblock posted: ” When I first saw today’s date in mm/dd/yy format — > 11/12/21 — I thought, “Well, that’s pretty cool. It’s all 1s and 2s.” And > then I thought, as I’m sure you did, “In ternary, that’d be 376,” because > everyone thinks in ternary, ri” >