They have had the best math models for about a year most folks just didn't know about it. You can't find inference on APIs, but I run these at home, this is also the advantage of open models.
https://huggingface.co/deepseek-ai/DeepSeek-Math-V2 https://huggingface.co/deepseek-ai/DeepSeek-Prover-V2-671B
You run a 671B model at home?
Vertex AI has had deep seek available via API for a while