Nólimon - The son and heir of Elros.  He, however, did not accept the throne.

"He was born in the year 61 of the Second Age and died in 471.  He was called Nólimon for his chief love was for ancient lore, which he gathered from Elves and Men.  Upon the departure of Elros, being then 381 years of age, he did not ascend the throne, but gave the sceptre to his son.  He is nonetheless accounted the second of the Kings (but not on this chart), and is deemed to have reigned one year.  It remained the custom thereafter until the days of Tar-Atanamir that the King should yield the sceptre to his successor before he died;and the Kings died of free will while yet in vigor of mind." ~Unfinished Tales (The Line of Elros: Kings of Númenor)