This challenge is to find at least twenty-five Groundspeak caches with all-numeric GC codes. For example, GC28187 is an all-numeric code, GC2F7AA is not. These may be caches found or placed at any time since May 2000; the only condition is that they must have been in active status (not unpublished, disabled or archived) when you found them. Please list the qualifying caches in your log or place a picture of a GSAK, Excel, or whatever list.
Older caches are more likely to have all numeric tags than newer ones, but they are scarce. The probability now of a five-digit base-31 listing having only numbers is [(10/31)^4] or roughly one in 92. The overall difficulty suggests how hard it may be to find twenty five of them. Special regards to those who've found GC30 or GC92!
The location is quite close to some places that are also big on numbers. Street parking is free, but may be difficult at certain times.
Thanks to Chrysalides for posting a useful GSAK macro in the logs and correcting my arithmetic, and congratulations to oaknest and the lovely CarlottaP for the FTF.