Applying Late to Mathematics Graduate School
There's an easy way out of this dilemma: talk to your professors now, tell them that you intend to apply to graduate programs in another year, and that you hope they will be willing to write recommendations.  The professors can then draft a letter right away, or at least notes for a letter, while their memories of you are still fresh.  When the time comes for you to apply, they can update their draft to discuss any additional accomplishments you have achieved in the intervening year, and send it in.
I don't think that a two-year gap between undergrad and grad school is likely to make a big difference in admissions, especially if you describe it as your plan all along.  You just want to avoid giving the impression of &quot;I went to go work in industry but immediately discovered I hated it / got fired / etc, so now I'm applying to grad school because I can't think of anything else to do with my life&quot;. If it were five or ten years, there might be some impact, but that's not the case here.