Given the task definition and input, reply with output. In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

From lanthanum ( 57 ) to lutetium ( 71 )

The lanthanide elements are the group of elements with atomic number increasing from 57 ( lanthanum ) to 71 ( lutetium ) .