Would you say the indefinite article 'a' goes with the phrase 'other activity' too?

Students analyze their own thought processes following a reading or other activity.

If so, what is the difference between that example and this in terms of how the article applies to other elements in the sentence?

Students should bring a pen and other brush.

Could I take the 'other brush' to mean 'another brush'?
My simple answer is that "a" doesn't go with the phrases after "or" and "and" in your examples.
Reading is an activity.
A pen is not a brush.
The two situations are incomparable. The second makes no sense.

You can interpret other activity either as the uncountable other activity or, borrowing the a from a reading, as the countable another activity.
Students: We have free audio pronunciation exercises.
Thank you so much, but I asked the question because I believe I asked a similar question in the past and a guru have answered it that the indefinite article does go with a phrase similar to 'other activity' in the original example sentence.

Normally, I think the word 'other' is used/left to modify an uncountable noun and not a countable noun, but I have seen cases where a countable noun is modified by an indefinite article, 'a', later in the order/sequence.
 CalifJim's reply was promoted to an answer.
Students: Are you brave enough to let our tutors analyse your pronunciation?