The number 42 is the final number in the numbers sequence. Below is a list of the appearances of this number in chronological order by episode, and the number 42 in real life.

In Lost:

• The average length of an episode (excluding commercials) is 42 minutes long.

Season 1:

"Exodus: Part 1"-

• Ana-Lucia sat in seat 42F.

"Exodus: Part 2"-

• Hurley's hotel room is 2342.
• Hurley's car traveled 42 kilometers before it broke down.
• There were 42 survivors that were still alive by the end of the season.

Season 2:

"Man of Science, Man of Faith"-

• The mural in the Swan had the numbers 42 and 108.

"Collision"-

• Locke was working on question 42 on a crossword puzzle. The answer was Gilgamesh.

"One of Them"-

• Kelvin Inman showed Sayid part of video reel

23108-42.

"Live Together, Die Alone"-

• The Address of the prison Desmond was at was Southway Garrison, 42 Berechurch Road.
• Desmond tells Libby he needs $42,000 to buy a boat.
• Kelvin Inman died when he was 42.

Season 3:

"A Tale of Two Cities"-

• Jack was working on a crossword with number 42. The answer was Necessary Evils.

"Enter 77"-

• There were 42 moves until inevitable checkmate in the chess game Locke played against the computer.

Season 4:

"Confirmed Dead"-

• The helicopter's number is N842M.

"The Constant"-

• The frequency used in Daniel's experiment is 2.342.
• The Black Rock auction number was 2342.

In Real Life:

• In the book The Hitchhikers Guide to the Galaxy, 42 is the answer to the ultimate question of life, the universe, and everything.
• 42nd Street in New York is a very main and popular street, including many landmarks such as the Chrysler Building, Grand Central Station, New York Public Library, and Times Square.
• 42 is a disastrous number in Japan; the pronunciation of the number sounds similar to "going to death" in Japanese.