>>> from serie_numerica import parell_senar_2
>>> round(parell_senar_2(185), 2)
48.3
>>> round(parell_senar_2(6135), 2)
913.2
>>> round(parell_senar_2(20), 2)
8.6
>>> round(parell_senar_2(90), 2)
26.25