Well, if you go far enough in math, you'll learn the i, j, etc. convention, which is where FORmulaTRANslation got it (unless otherwise declared, variable names starting with i through n are integer).

And you might learn it indirectly from all the people and code that follow this convention. In my case, it was FORTRAN first, albeit perhaps in the same academic year 1977-8 where I was introduced to i, j, etc. in Algebra II.