It's unusual for the largest city in a country to not be the capital, but I wouldn't say it's particularly weird.
Other examples include Canada (Toronto largest, Ottawa capital), Australia (Sydney largest, Canberra capital), China (Shanghai largest, Beijing capital), Brazil (Sao Paulo largest, Brasilia capital), and Nigeria (Lagos largest, Abuja capital). There are plenty more, although they're definitely a minority.
Europe is pretty much all largest-city-is-capital though, so maybe from a European perspective it's weird (European exceptions include Liechtenstein and Malta).
/diff
Other examples include Canada (Toronto largest, Ottawa capital), Australia (Sydney largest, Canberra capital), China (Shanghai largest, Beijing capital), Brazil (Sao Paulo largest, Brasilia capital), and Nigeria (Lagos largest, Abuja capital). There are plenty more, although they're definitely a minority.
Europe is pretty much all largest-city-is-capital though, so maybe from a European perspective it's weird (European exceptions include Liechtenstein and Malta).