If you set n=2^140, then sure, it’s constant. If instead you only have n<=2^140, then n varies across a large set and is practically indistinguishable from n<=infinity (since we get into the territory of the number of atoms in the universe), therefore you can perform limit calculations on it, in particular big O stuff.

In the article n was set to 5. All of those arrays (except maybe 1) have exactly 5 elements. There is no variance (and even if there was, it would be tiny, there is no point in talking about limits of 5-element sequences).

> In the article n was set to 5. All of those arrays (except maybe 1) have exactly 5 elements. There is no variance

No, the code was:

    # If there are < 5 items, just return the median
    if len(l) < 5:
        return nlogn_median(l)

> and even if there was, it would be tiny, there is no point in talking about limits of 5-element sequences

So your point is: not all constants are created equal. Which circles all the way back to my original point that this argument is pretty funny :)