In modern arithmetic textbooks, students are taught about alternate numeric bases. The notation for indicating the base of a number is to attach the base as a subscript. The subscript is itself a numeral in base ten.
My question is, when was that notation first invented? Who invented it? Where did it first appear in print?
I have a copy of Handbook of Mathematical Tables and Formulas, 5th ed., by Richard Stevens Burington, Ph.D., copyright 1973. It contains a section about alternate bases, including a description of this subscript notation. So it must predate 1973.
I found an archive copy online of the 1st edition, copyright 1933, which lacks this section, among many others. Apparently many topics were added to this work in the intervening 40 years. But this is not evidence that the subscript notation was invented during that period. It only shows that it rose enough in importance to get included in the Handbook.