[NightKnight]

His sons Fëanor, Fingolfin and Finarfin.
Fëanor's sons Maedhros, Maglor, Celegorm, Curufin, Caranthir, Amrod and Amras.
Curufin's son Celebrimbor.
Fingolfin's children Fingon, Turgon and Aredhel.
Fingon's son Gil-galad.
Turgon's daughter Idril.
Aredhel's son Maeglin.
Idril's son Eärendil.
Eärendil's sons Elrond and Elros.
Finarfin's children Finrod, Orodreth, Angrod, Aegnor and Galadriel.
Orodreth's daughter Finduilas.
Galadriel's daughter Celebrian.
Celebrian's children Elladan, Elrohir and Arwen.
Arwen had a son, Eldarion, and some unnamed daughters.

So that makes 31, plus the unnamed daughters. Or do you mean 5th generation including Finwë? Then we'd have to remove Elrond, Elros, Eldarion and the daughters, and we'd get 28.