Yes, here is another example of major work in this area:

https://arxiv.org/html/2605.22763v1

> Our most capable agent autonomously resolved 9 of 353 open Erdős problems at the per-problem cost of a few hundred dollars, proved 44/492 OEIS conjectures

Many less important Erdos problems have been solved by amateurs prompting ChatGPT 5.{3,4,5,6} Pro using their $200 subscription.

https://blob.byteterrace.com/public/bds-theorem.html

I have no affiliation whatsoever with any AI company, nor any formal education outside high school, for what it's worth. Simply being curious and persistent can get you quite far in my anecdotal experience.

> Also, have there been examples of researchers not affiliated with OpenAI (or another LLM creator), who have done something similar?

A couple small ones that I've seen (example here [0]), but not anything of the magnitude that OpenAI and Anthropic have put out. Likely just related to token limits.

> Another question I have is whether or not OpenAI 'simply' hired capable combinatorics researchers to work on problems, and they have, and the use of the model is incidental / secondary to their work.

I think their output has reached a level that precludes this possibility, but I of course don't have any hard proof.

[0]: https://www.reddit.com/r/math/comments/1uxj3cy/after_openais...