Nunes, R. M.2017-05-012017-05-012017-05-01201710.1112/S0025579317000043https://infoscience.epfl.ch/handle/20.500.14299/136661WOS:000397963300009We prove an asymptotic formula for squarefree numbers in arithmetic progressions, improving previous results by Prachar and Hooley. As a consequence we improve a lower bound of Heath-Brown for the least squarefree number in an arithmetic progression.text::journal::journal article::research article