The number 815 is a very consistent number in Lost, which is a combination of 8 and 15. Below is a list of the appearances of this number in chronological order by episode, and the number 815 in real life.

In Lost:

Season 1:

""Pilot:Pilot: Part 1"1-"-

• The plane that crashed was Oceanic Airlines Flight 815.

""RaisedRaised By Another"Another-"-

• Claire's appointment for the adoption signing was at 8:15.

""WhateverWhatever the Case May Be"Be-"-

• The safe deposit box Kate robbed was 815.

""Homecoming"Homecoming-"-

• Charlie was trying to sell the model C-815 copier.

""DeusDeus Ex Machina"Machina-"-

• At the toy store Locke worked at, regular balls were in aisle 8, Nerf balls were in aisle 15.

""BornBorn to Run"Run-"-

• Kate and Tom buried the time capsule on 8/15.

""Exodus:Exodus: Part 1"1-"-

• Michael and Walt's hotel room was 815.

Season 2:

""ManMan of Science, Man of Faith"Faith-"-

• Adam Rutherford's time of death was 8:15.

""Lockdown"Lockdown-"-

• The real Henry Gale's address was 815 Walnut Ridge Road.

Season 3:

""FlashesFlashes Before Your Eyes"Eyes-"-

• A delivery man was sending a package for 815.

""GreatestGreatest Hits"Hits-"-

• The Looking Glass logo is a rabbit with a clock pointing to 8:15.

Season 4:

""TheThe Beginning of the End"End-"-

• The letters H O appear at Santa Rosa, which the numerical value is equal to 8 and 15.

"There's No Place Like Home: Parts 2 & 3"-

• Before shooting a man at Santa Rosa, Sayid asks what the time is, to which he replies 8:15.

In Real Life:

• South Korea's and India's Independence Day is 8/15. South Korea even has a soda called 815 soda.
• The Hiroshima bomb was dropped on August 6th, 1945 at 8:15 AM.
• 8/15 is a German term meaning "boring".