I'm not an expert, but, in my opinion GMAT doesn't go too far with recursive sequences.
most of the questions I've seen are like this one - substituting numbers into a term repeatedly till you get the answer. Therefore, the most important things on these questions are not getting bogged down by the length of calculations and not making a stupid calculation error. ( I wrote things way neater than usual on my scratch pad when I had to do recursive calculations
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