It seems like density that can be used and successfully get fruit/grain/veg is determined mostly by water availability and nutrient availability. If the spot has been topped off with compost and you get good rainfall or are watering during dry spells then you can probably go pretty tight. If it’s not so great soil, nothing added, and dry farmed with lower rainfall then you’ll probably need a wider density to get good yeild. From there it’s down to pest and disease pressure. I don’t know how much that will affect corn, my first thought is more like tomatoes and blight where more density and more humidity makes for more blight in general.
This thread talks about spacing corn- Let's talk about laying out corn and friends