@article{NSJOM_2003_33_2a_5,
     author = {F. Luca},
     title = {Positive integers n|aa(n) -1},
     journal = {Novi Sad Journal of Mathematics},
     pages = {49-66},
     publisher = {mathdoc},
     volume = {33},
     number = {2},
     year = {2003},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_2003_33_2a_5/}
}