I tried the search system on the main page and the advancen version. I could not found a option that give the result you asked for.
The closes was search for a single letter
and so on but the index system splits words by non letter and "3/1 D/T" is a hit
it could give you potential caches to look at manually. Only letters are index so @ cant be searched for
If only regexp search was possible but they would be expensive
The only way to do the search i know about is using GSAK
RegEx search on cache namne with
gives the correct answer to your question