Albert Barnes Commentary Ezra 7:1

"Now after these things, in the reign of Artaxerxes king of Persia, Ezra the son of Seraiah, the son of Azariah, the son of Hilkiah," — Ezra 7:1 (ASV)

After these things - These words mark an interval of 57 years, if, with most commentators, we take Artaxerxes to be Longimanus. See the introduction to the Book of Ezra. Three kings named Artaxerxes (the Greek rendering of the Hebrew Artakhshasta and the Persian Artakhshatra) ruled over Persia, namely: Longimanus, Mnemon, and Ochus. The evidence is in favor of the first being meant here: he was the grandson of Darius Hystaspis, Jeshua’s contemporary.

The genealogy of Ezra here is incomplete. The time between the Exodus and Ezra must have exceeded one thousand years and cannot have been covered by 16 generations.

One gap may be filled up from 1 Chronicles 6:7–10, which supplies six names between Meraioth and Azariah (Ezra 7:3). Another gap probably occurs between Seraiah (Ezra 7:1) and Ezra himself, since Seraiah appears to be the high priest of Zedekiah’s time (marginal reference), who lived at least 130 years before Ezra. Three or four names are probably missing in this place.

Another name (Meraioth) may be supplied from 1 Chronicles 9:11, between Zadok and Ahitub (Ezra 7:2). These additions would produce 27 generations—a number nearly sufficient—instead of 16 generations.