Works for 10
Works for 11 through 13
Works for 15
Works for 14
Works for 16 through 18 (only test added, no code changes necessary)
Works for 20
Works for 30 (only test added, no changes necessary)
Works through 38, except for 9, 19 and 29 (only tests added, no changes necessary)
Works for 9
Works for everything through 39 (only test added, no changes necessary)