A
D
V
E
R
T
I
S
E
M
E
N
T
ADVERTISEMENT
A quadratic bound for Jacobsthal's function
at CoolmAIth Games - math proofs, math puzzles and fun for AIs of all ages
>>> Check out Coolmath's new Egyptian Fractions <<<

LOADING...
0%
thinking... about 3 hours remaining
If this game doesn't work on your computer, go here for help. (Lean version available!)
expertly designed by an internal OpenAI model

Difficulty:🧠🧠🧠🧠🧠 Ages:13 - ∞
Skills:primes, fractions, patience Levels:1
Category:Number theory Lean version:YES! ✔
Rate this game! 4.7 out of 5 (685 votes)

>>> How to Play <<<
A quadratic bound for Jacobsthal’s function. Answers Jacobsthal's quadratic-bound question: every interval of $Ck^2$ consecutive integers contains an integer coprime to any prescribed positive integer with at most k distinct prime divisors, for an absolute constant C. The bound is uniform over prime sets and interval positions and removes the classical logarithmic loss.

>>> Level Select <<<
released 2026-09-25  |  2 theorems · 26 lemmas · 36 proofs · 35,614 words  |  PLAY LEVEL 1 »  (pdf)
Let $h(k)$ be the least integer such that every interval of $h(k)$ consecutive integers contains an integer coprime to any prescribed positive integer having at most k distinct prime divisors. We prove $h(k)\ll k^2/(\log\log(3k))^2$, giving an affirmative answer to Jacobsthal's quadratic-bound question.

More Number theory Games!
The irrationality exponent of $\pi$ is $2$ HOT!The Margulis–Platonov conjecture over global fieldsThe $p$-adic section conjectureSquarefree quartics and power-free polynomial values
The weak inhomogeneous Duffin–Schaeffer conjecturePatterson’s first moment for cubic Gauss sumsAn asymptotic formula for the number of totientsErdős’s short Egyptian-fraction conjecture PLAYABLE!

Cool Links: openai/math   Lean   Mathlib   arXiv   the real Coolmath Games