can you just add 7x7 ingame, why are you making me get paper out
nvm i did it in penpa, solution wasn’t interesting, i would actually advise people not to waste time on that. i looked up the problem and after 5x5 16, 11x11 68 is the next interesting case, then 17x17, 23x23, 29x29…
there is a pattern that lets you increase the packing density every 6n+5, but it is an open problem whether you can ever do better than that and increase the density at 6n+3. for a humanly interesting progression, do 5x5 16 -> 7x9 37 -> 11x11 68.