I have one of those hampton bay fans with the stupid A15 intermediate base bulbs, I can only find bulbs like this that are for appliances like microwaves locally. There was a thread for this same question and it looks like the guy found a solution but the link was removed here's that thread https://www.askmehelpdesk.com/electrical-lighting/convert-a15-intermediate-socket-a19-standard-socket-231481.html anyone know where I can find a conversion socket?

Here is one place you might be interested in. They have what your asking for.

Light Bulb Adapters, Light Bulb Socket Adapters, Lamp Base Adaptors from Norman Lamps, Inc.