The low dose oxycodone formulations (percocet) have acetaminophen in them. I do not suggest snorting these, consider that only about 1% of the material you're trying to snort is actually oxycodone while the rest is tylenol and filler.
5mg is a low dose, thats what they prescribe you after standard procedures and oral surgery. A fourth of an 80, or 20mg seems the best dose for a first time user in my opinion. (If all you want is a buzz then sure go lower.)