Feature summary (what you would like to be able to do and where):

Transcribe a factorial using an older form of notation with the Math extension.

https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Elementary_algebra_%281896%29.djvu/page367-1948px-Elementary_algebra_%281896%29.djvu.jpg contains an equation with an older form of factorial notation.

This is not currently provided by the supported functions usable in MATH tags.

https://tex.stackexchange.com/questions/117497/typesetting-old-fashioned-factorials suggests 2 possible approaches.

Would it be possible for some kind of \oldfact function to be implemented for MATH to support the Wikisource transcription, of pages like this?