I found (6, 8, 7) by some trial and error, but also ruling out combinations that logically wouldn't work. But no way was I going to find (46, 7, 19). Even Wolfram Alpha failed at that. And forget about proving that those were the only two solutions!
This manga started badly, tailed off a little in the middle, and the less said about the last few chapters the better. But apart from that, it's excellent!