If the formula generates an integer sequence, then searching that sequence on OEIS should give a lot of good information.
Claude
Slightly related: https://oeis.org
+1 to wolfram alpha. But just like Chegg, I thought wolfram alpha would be harshly affected by the AI disruption.
I used it a lot in college but never since. Are current college folks still using it?
Wolfram Alpha
The encyclopedia of integer sequences can be quite useful: https://oeis.org/
ProofSouq.com! https://proofsouq.com
8M+ search index entries over Lean and Rocq corpora and growing; propositions only for now, so more oriented towards premise retrieval at the moment.
Lean also has https://www.leanexplore.com and https://loogle.lean-lang.org/