I have been working on a problem (not in mathematics) for a while and at the core there is a simply stated mathematical problem which I really cannot solve. I have tried asking colleagues but they can't either. As far as I can tell it is not equivalent to some known problem either.
I am not myself a professional mathematician so I see no prospect of my being able to solve it. However I would love to know if it is true or not. Is there some forum to place non-trivial simply stated mathematical conjectures? Or should I just put the whole paper on the arXiv and forget it?