Twitter_induction.png I saw a funny thing on Twitter. What does it say?

It asks what comes after 5, 7, 11, 13, 17, 19, 23. There are two options: 25 and 29. I can see that people hesitate: It’s almost half-half! I don’t understand why!

Why what? There’s an obvious answer.

Which is? You have to select the next prime, which is 29.

Pablo.png
Ha ha! You are reacting exactly as "MC Pablo"!
It’s in French.

So you didn’t see the pattern +2 +4 +2 +4 +2 +4. Ah! OK, I understand why 25 makes sense, now.

So it’s clear which is the "correct" answer. Yes. You just choose the less complex one.

And so you will favor 25, as the Turing machine that computes +2, +4, +2, +4... is smaller than the one that computes prime numbers. No, I was about to say that 29 was simpler!

You can’t say that! Yes I can! If you already know what primes numbers are, it’s simpler to say "retrieve the next prime".

Ok, I agree that the best induction depends on what you already know. Anyway, I had a look at what oeis.org says about this series.
"Numbers congruent to 1 or 5 mod 6",
"Numbers n such that (2n + 1)/3 is prime",
"nth irreducible polynomial over Q (with coefficients 0 or 1) evaluated at x=2".

The first one is the same as +2, +4, +2... Yes, no... Not exactly. But anyway, the other ones are really crazy!

You say this because they are way too complex, as compared with merely saying 5, 7, 11, 13, 17, 19, 23. Yes, I guess so.
Maybe complexity offers us a way to measure "craziness" 🤪!