For example here the sentence is, "Consider any sequence of data points x0, x1, x2,... in R" It messes up my mind when I can't loudly read something.
How is ... (dot dot dot) pronounced in such a sentence?
What I've heard most often is simply three consecutive "dot"s (I am reminded of the beginning scene in Mamma Mia where they read the mother's diary), but you could always substitute it.
Some phrases to try might be et cetera
and others especially of the same kind : and so forth —abbreviation etc.
or "and so forth/on", or ad infinitum
without end or limit
Mathematician here! Personally, I do not read such an expression literally. So, as strange as this may seem, my answer to you is: "Forget about trying to read the '...' out loud in any meaningful way. Instead, focus on understanding the entire statement."
In this example, the writer is saying, "There is a countably infinite sequence of real numbers," and that they are choosing to label that sequence with indices (plural of index) that are non-negative integers. When I read that, in my mind, I picture an infinite list of numbers, starting at some point on the left (that's x0) and continuing off to the right, with no end. My eyes and brain scan the expression, but I do not attempt to "verbalize" those symbols in the way that you seek. Instead, the symbols, as a whole, convey the concept of an infinite, ordered sequence.
I know this may not be exactly what you want, but I do hope you find it helpful. It sure helps me.