@article{JIS_2009__12_3_a2,
     author = {Luca, Florian and Tipu, Vicentiu},
     title = {On positive integers $n$ with a certain divisibility property},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {12},
     number = {3},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2009__12_3_a2/}
}