ATLAS results on charmonium production and B_c production and decays

Recent results from the proton-proton collision data taken by the ATLAS experiment on the charmonium production and on the B_c production and decays will be presented. The measurement of J/psi and psi(2S) differential cross sections will be reported as measured on the whole Run 2 dataset. The measurement of the differential ratios of the B_c+ and B+ production cross sections at 8 TeV will also be discussed. New results on the B_c decays to J/psi Ds(*) final states obtained with the Run 2 data at 13 TeV will be shown.