@article{JIS_2009__12_8_a7,
     author = {Janji\'c,  Milan},
     title = {Some classes of numbers and derivatives},
     journal = {Journal of integer sequences},
     year = {2009},
     volume = {12},
     number = {8},
     zbl = {1213.05013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2009__12_8_a7/}
}