What was the country with a population density per km² of 3.5/km² (/sqmi)?
create table table_26769_1 (country_or_territory_with_flag varchar, population_density_per_km² varchar, PRIMARY KEY (country_or_territory_with_flag))
select country_or_territory_with_flag from table_26769_1 where population_density_per_km² = "3.5/km² (/sqmi)"