@article{hrj:156, title = {Carmichael number with three prime factors.}, author = {D R Heath-Brown}, url = {https://hrj.episciences.org/156}, doi = {10.46298/hrj.2007.156}, journal = {Hardy-Ramanujan Journal}, issn = {2804-7370}, volume = {Volume 30 - 2007}, eid = 1, year = {2007}, month = {Jan}, keywords = {Ramanujan sum, Upper bound, Three prime factors, Carmichael numbers, [MATH]Mathematics [math]}, language = {English}, }