Thanks, but I'll stick to mostly lurking for the time being

. Anyway, Skyblazer, you're doing a fantastic job as the "designation guru" on this forum

!
"A-18A" is also in that MDS database while A-16 is not. But yes, A-14 is (or was) the next regularly assignable number in the A-series.
In just in case someone asks about the mentioned "MDS database": It's not classified, but there is no public access to it. In May 2014, I FOIA-requested a full excerpt. and got a PDF:
http://www.designation-systems.net/usmilav/original-docs/Tab_1_A8_PDF_MDS_listing_20140509.pdf
There are very few "weird" entries (like A-14A), but mostly it's just a somewhat nerdy reference

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