Not good

The array is either entirely comprised of odd integers or entirely comprised of even integers except for a single integer N

Ok, but the description says it won't happen.

oh damn ive learned so much from doing this, thx y all

The description mentions from a to b (inclusive). Ins't this answer wrong in that sense ?

irb > (1...3).to_a
=> [1, 2]

My concern exactly.

I like it!!!

Anyone want to break this down for me? I still don't really get how to set up procs like this.

You could do ".digits.reverse" instead of ".to_s.chars" too! :D
You wouldn't need to convert them back to integers later on if you do that.

It's an offset. It sets starting value of the index (default is 0).

https://ruby-doc.org/core-2.4.1/Enumerator.html#method-i-with_index

It's awesome!

Nice!