Seven

Bungie Studios has long enjoyed using the number seven in its games in as many ways as possible. Therefore, in many of their games, this eccentric idea has caused a wild hunt for as many references to the number as possible (even if they are unintentional). In order to keep the list relevant, please refer to the following guidelines:


 * 1) No seven character words/phrases.
 * 2) Subject must be directly related to Halo.
 * 3) Numbers cannot just merely contain 7 as a digit. (e.g. no 17)
 * 4) If numbers are to be placed into equations, the operations are to be kept consistent. (e.g. no 1+2+8-1+6-9=7)
 * 5) No fan fiction, including machinima such as Red vs Blue.

Halo: The Fall of Reach

 * The book takes place, for the most part, in 2525, 2 + 5 + 2 + 5 = 14, or 7 &times; 2. It could also be written as 2 + 5 = 2 + 5. They are all equal to 7.
 * The children observed 7 wolves attack a moose in class.
 * On October 7, 2525, three UNSC vessels were sent to investigate why the Colonial Administration Authority had lost contact with the Harvest system.
 * A destroyer was only 7 meters longer than a frigate.
 * Keyes could only count 7 UNSC vessels still intact after the battle of Sigma Octanus.
 * Four Covenant frigate ships are an even match with 7 UNSC destroyers.
 * Jericho VII. VII = 7 in Roman Numerals.
 * Lieutenant Keyes notes he graduated from UNSC OCS "only seven weeks ago."
 * Lieutenant Hall has written seven physics papers on Slipspace communications.
 * Hall reports a collision in seven seconds.
 * They are surrounded by seven soldiers.
 * Cortana accessed SATCOM observation beacon 419. 4 + 1 + 9 = 14 = 7 + 7
 * 7 Covenant frigates were pursuing the Pillar of Autumn
 * The Pillar of Autumn carried 7 C709 Longsword-class Starfighters.
 * The First SPARTAN introduced after John was Sam-034(0+3+4=7)

Halo: Combat Evolved (and Halo: The Flood)

 * In the first cutscene of the game Cortana says to Captain Keyes she destroyed " three, make that four" covenant ships (3+4=7).
 * The escape pod used by the Master Chief to escape from the Pillar of Autumn is number 61(6+1=7).
 * It is possible to kill Sergeant Major A.J. Johnson a total of seven times.
 * There are seven Halo Installations.
 * 343 Guilty Spark: 343 is 73. Additionally, G and S (as in "Guilty" and "Spark") are respectively the 7th and 7th-from-the-last letters of the English alphabet.
 * In Chapter Seven of The Flood, the date is "Seventh Cycle, 49 units '(Covenant Battle Calendar)'". 49 = 7 &times; 7
 * In Halo: The Flood, Silva wishes he had 7 Lt. Mckays'.
 * The Kanji character for seven (七) or a European 7 (a line through the middle of a regular 7 to differentiate it from 1) depending on how you look at the pistol is on the M6D Pistol.
 * You need at least seven needles from the needler to make an explosion.
 * Echo 419: 4 + 1 + 9 = 14; 7 &times; 2.
 * Cortana instructs Echo 419 to extract them at external access junction 4C. C is the 3rd letter of the alphabet, 4+3=7
 * The last Longsword on the Pillar of Autumn was in launch bay 7.
 * On the level The Maw the countdown timer for the destruction of the engines is stopped by 343 Guilty Spark at 13:30. 1+3+3+0=7.
 * There are seven locations used in the levels. The Pillar of Autumn used the same location as The Maw, The Truth and Reconciliation used the same location as Keyes, and Assault on the Control Room used the same location as Two Betrayals. The locations from Halo, The Silent Cartographer, 343 Guilty Spark, and The Library are not reused.
 * The alphanumeric characters of MA5B (as in MA5B Assault Rifle add up to 21. M=13+A=1+5+B=2=21=7x3
 * Sergeant Johnson appears in 7 levels.
 * If you look at the sun, then turn slightly in any direction, you can see that there are seven circles in the lens flare.
 * Both Cortana and Spartan have 7 letters.

Halo: First Strike

 * There are seven Covenant ships in the system after Halo's destruction.
 * Spartan-104 accidentally spams FLEETCOM 7 during the descent of the Pelican Bravo 001.
 * Cortana has to manipulate 88 variables. 8+8 = 16, 1+6 = 7.
 * Cole Protocol, Subsection seven, is stated.
 * The Spartans on Reach arrive at ODG Facility A-331. 3 + 3 + 1 = 7
 * The Covenant flagship Ascendant Justice has seven plasma turrets.
 * The Spartans try to save Reactor Complex Seven.
 * There are seven surgical bays in the infirmary of CASTLE Base.
 * As she is deleting Araquiel, Dr. Halsey taps the level seven security barriers.
 * Ascendant Justice arrives in Epsilon Eridani 700,000 kilometers from the system's center.
 * John says that it is the seventh time they have trained with Tango Company.
 * After their mission against Tango Company, the Spartans are supposed to rendezvous with Chief Petty Officer Mendez at 0700 hours.
 * There were seven service drones aboard the Gettysburg.
 * Dr. Halsey boosts counterintrusion measures to level seven.
 * The dead crew of the Gettysburg is placed in cargo bay seven.
 * The Spartans must move seven kilometers further up the top lobe of the Unyielding Hierophant. And they did this in eleven hours. (11 hours, 7 km. 117)
 * The Master Chief sets his Lotus Anti Tank Mine detonator for seven seconds.
 * Excluding Section 0, there are 7 sections in Halo: First Strike.

Halo: Ghosts of Onyx

 * The Spartan IIIs of Beta Company had been launched from Slipspace seven hours ago.
 * Seven Covenant cruisers appear.
 * K7-49: 49 = 7 x 7
 * A group of Sentinels were linked in a triangle, numbering 49.
 * One hour and seventeen minutes were left until the door closed, which adds up to 77. Interestingly, if displayed on a digital clock, the time would appear as 1:17, or 117 (Master Chief's Spartan number).
 * All medicines used in the Spartan-3 augmentations have the number seven in their label.
 * "Only the seven Spartans here."
 * "What Sangheili Major would dare disobey a Ship Master who had led seven glorious campaigns against their enemies?"
 * "The seven Sentinels adjusted their aim and their spheres glowed red, amber, and then glistening gold."
 * The ceiling above where the Spartans landed in the construct was 7 sided.
 * The Semi Powered Infiltration Armor has 7 minutes of breathable air.

Halo 2

 * In Halo 2 there are 7 Covenant races seen: Grunts, Jackals, Drones, Hunters, Brutes, Elites, and Prophets
 * In Halo 1 and Halo 2 the year is 2552. 2+5=7 &times; 5+2=7
 * Master Chief's new armor MARK VI: alphanumeric=13+1+18+11+6(VI)= 49 (7x7=49)
 * Halo 2s highest multi-kill medal is Killamanjaro which is seven kills within 4 seconds of each other, also 7 stars on medal
 * On "Cairo Station", during the end cutscene where the Master Chief reactivates the bomb, it takes 7 seconds to explode.
 * If you look closely at the Master Chief's helmet, you can see a faint 7 (This is best viewed in the 1st cutscene on Metropolis).
 * You need to get seven needles in a target to make it explode.
 * It takes 7 shots to lower the pistons in the Sacred Icon level.
 * 7 pellets are shot out of a shotgun shell.
 * Seven Shotgun shots to the front of an empty Warthog will destroy it
 * 2401 Penitent Tangent: 2401 is 74. Also, 2+4+0+1=7.
 * Serial number of the In Amber Clad is FFG-142.  1 + 4 + 2 = 7. Also 14/2=7.
 * 2401 times 343 is equal to seven to the seventh power (823,543).
 * The Cairo Station is identified as UNSCDF-ODA142 CAIRO. 1 + 4 + 2 = 7
 * One of the special Zanzibar Signs occurs on 07/07.
 * The Gravemind speaks mostly in heptameter, a poetic style with seven meters per line.
 * On Outskirts, in the small dark room where the IWHBYD skull is located, there is a number 7 on the wall.
 * The IWHBYD skull can only be found once every 7 times you play the level. Also, "I Would Have Been Your Daddy" has 7 syllables. The skull is named after a line in the campaign, which also includes the words, "but the dog beat me over the fence." Including these words, there are 16 syllables in all (1+6=7).
 * At the end of the credits the "t" is replaced with a seven in the sentence "And a whole load of people we didn't get time to 7hank"
 * To obtain the IWHBYD skull, one must face seven waves of Ultra Elites, with seven elites in the seventh wave
 * On the level Cairo Station where the Arbiter gets branded with the Mark of Shame, there are seven tiers of bleachers for the audience.
 * There are 7 game types.
 * In Outskirts on your way to the blind skull there is a sign bearing the number 7 nailed into the wall.
 * Near the end of Outskirts in the tunnels when the Covenant regroup. At certain parts of the tunnel "C-4" can be read above on the sides of the road. C=3, 3+4=7
 * Also C-4 is the Hanger the Master chef escaped halo onboard a Longsword in.
 * There are currently 7 Covenant vehicles. Wraith, Ghost, Spectre, Scarab, Banshee, Phantom and the Shadow.
 * There are also only 7 usable vehicles in the game. They are the Scorpion, Wraith, Spectre, Warthog, Gauss Hog, Ghost, and Banshee.
 * In a deleted scene, a longer version of the cutscene at the start of "Sacred Icon", Truth and the Arbiter were viewing seven murals that showed how the Covenant had grown.
 * On Miranda Keyes' cheek, there is a faint seven.
 * The ODSTs seen in-game belong to the 7th Orbital Drop Shock Trooper Division.
 * After the half-closed highway door in Metropolis, before the section "This Town Ain't Big Enough for the Both of Us," you go through a tunnel, turn to your right and you will see some squares with numbers in them that are 2, 2, and 3. 2+2+3=7
 * You fight in 7 levels as the Master Chief (Cairo Station, Outskirts, Metropolis, Delta Halo, Regret, Gravemind and High Charity.
 * When you zoom in either the Covenant Carbine or the Fuel Rod Cannon, there are seven hexagons making up the center.
 * In Metropolis, near the end of the level where you have to destroy the Scarab, there is the sergeant with the communicator. On the back of this communicator is the Hindi word for seven, written in the Hindi script.
 * In The Armory there are seven visible MAC cannons (six out in the distance and Cairo itself), but only in the first and second space part.
 * Firing the Plasma Rifle until it overheats will drain 7 power units, assuming it is not burst fire.
 * Counting the "training level" (Armory), there are 14 levels. 14/2=7
 * In Headlong, there is a sign in the building next to the Banshee spawn point that reads: 2,2,3,W. 2+2+3=7.
 * On the multiplayer level Zanzibar there are seven palm trees and seven cylinder crates
 * On Headlong near the bridge which connects to the Needler Building there is a piece of paper with the number seven pinned on the wall
 * In Headlong the maximum ammunition in the building which houses mostly Covenant weapons is 7 canisters or 700 fuel units.
 * The multiplayer map Containment has 7 "pyramid fusion coils"
 * The multiplayer map Lockout has 14 Forerunner fusion coils. 14/2=7
 * The Grunt Birthday skull has 7 grunts around it.
 * The multiplayer map Terminal has a large 7 on the station building probably meaning it is station 7.

Halo 3

 * There are seven races within the Covenant Loyalists - Prophets, Brutes, Grunts, Drones, Jackals, Hunters, and Engineers
 * It takes 7 seconds for the bridge on Last Resort to lower itself onto the wheel.
 * By the end of Halo 3, seven forms of the Flood have been seen in the trilogy (not including the deleted Flood Juggernaut in Halo 2). These are: Infection, Combat, Carrier, Pure, Prophet, Proto-Gravemind, and Gravemind.
 * The UNSC Forward Unto Dawn has the number 7 on the front of it.
 * It takes seven needles to make a target explode.
 * If you draw a line between Mount Kilimanjaro (in the background of the Halo 3 E3 trailer), Mombasa and Zanzibar island you get a huge 7.
 * The release date was September 25 2007. 2+5=7
 * September was the seventh month in the Roman calender until 153 BC. As well in Latin septi means "seven" and septem means "seventh".
 * There are 49 confirmed achievements in Halo 3. 49=7 &times; 7
 * “The casing is constructed of an unusual porous metallic compound. Shrapnel from the Type-2 reaches a temperature of approximately 270 to 315ºC and retains that heat for upwards of seven seconds. By design.” Taken from Bungie.net on spike grenades.
 * There are 7 large objects in the background of Sandtrap, the six pillars and The Aegis Fate Frigate.
 * The CQB armor was designed using feedback from the Jericho VII theater.
 * ONI Recon Team 111 was the first UNSC unit to see the Forerunner Ark on Earth. 111 = 7 in binary (4+2+1).
 * In the Halo 3 museum Pawel Czernek mentions that "on the seventh day we ran out of ammo".
 * In the mission Crow's Nest, a rocket has the number 7 on each side, making 4 7's, or 7777.
 * The maximum amount of budget you can get on Forge is 700.
 * Last Resort (Level) is Zanzibar Municipal Turbine 7.
 * The SMG has a scratch in the shape of a 7(easier to see if gun is aimed at sky or near a light source).
 * If you're on open ground it takes 7 seconds to gain full speed in a mongoose.
 * It takes 7 seconds for 343 GS to explode after being dealt the fatal shot in the level Halo.
 * It takes 7 seconds from being infected by an infection form to turn into a combat form.
 * In the level Cortana, in the beginning of the cutscene where you rescue Cortana, there is 7 seconds of silence before she says "You found me".
 * High Ground has a vague "7" shape in the middle of it.
 * After Truth's first speech (after activating the rings) on the level The Covenant ("How could I have known the Parasite..."), it takes seven seconds for his hologram to disappear.
 * There are 7 terminals to find to unlock the Marathon Man achievement.
 * In the last scene there are seven gunmen at the memorial. (Please note that this was not planned by Bungie. In modern military tradition, a 21-Gun Salute used to salute the fallen consists of 7 riflemen firing three shots each.)
 * At the beginning of the level The Covenant there are 5 Pelicans and 2 Elite Phantoms, adding up to 7.
 * The seventh level of the game (The Covenant) is the last level of the series (chronologically) where you fight against covenant enemies.
 * On the side of the Warthog, below where the driver and passenger get in, just above the side skirts, there are 7 dashes.
 * There are 9 levels (not counting "Arrival") and 13 unlockable skulls in Halo 3.  9 &times; 13 = 117
 * In the Citadel on the level "The Covenant", there are seven rings, Ring 1 being closest to the lift and Ring 7 being closest to Truth. In order to find the "I Would Have Been Your Daddy" skull (which has a seven-syllable name), you have to jump through four of the rings seven times.
 * In this order: 4 6 5 4 5 3 4.  4 + 6 + 5 + 4 + 5 + 3 = 27,   also the last two rings are 3 and 4:   3 + 4 = 7
 * Only seven Sangheili ranks are seen in Halo 3.
 * In the multiplayer level, The Pit there are 7 Pelicans in the airfield (the area on the other side of the wire fence)
 * When dual wielding SMGs, it takes 7 seconds to run out of ammo if you hold down the trigger.
 * In the level Crow's Nest, when you first take control of the Master Chief, the emergency power generators on the far side of the room, where you need to go to get the Black Eye Skull, have the writing "EPG 2401". 74 = 2401. Also, 2+4+0+1=7. Also 2401 is the number of the other monitor you see in Halo 2, 2401 Penitent Tangent
 * When Johnson Gives you a Spartan Laser during "Halo" to kill 343 Guilty Spark with, it always has a 7 for the ten's digit in the remaining battery power. (unless you have the Famine skull on).
 * The Scarab, once the core has been compromised, takes 7 seconds to explode.
 * If you exit Epitaph in pan-cam mode, there are 7 lines in the dirt surrounding the tower that houses the map.
 * The Human-Covenant War ended on March 3rd 2553 (3+3+2+5+5+3=21) 21/3=7
 * In Tsavo Highway the doors at the start of the level all have the number 7 on them.
 * A single Spartan Laser cost more to produce than 7,266 frag grenades. 7+2+6+6=21. 21/3=7
 * There are 5,632 spartan armor permutation varieties available(5+6+3+2=16 / 1+6=7)
 * In the multiplayer level Sandtrap, the UNSC frigate, Aegis Fate, has a number 7 surrounded in a star on the side.
 * Including Arrival, there are 7 campaign levels in which Cortana does not physically appear.
 * When Miranda Keyes dies, there are 7 spikes from the Brute Spiker lodged in her back.
 * In the Level The Covenant, there are seven Elites that help you. (not including the Arbiter or the other Elites in 3 or 4 player co-op)
 * Not Including Arrival There are 7 levels that the cortana and gravemind moments acore. (Spelling)

Halo Wars

 * A vehicle with the number 3, 1, 3 again, and the letter G appears. G is the seventh letter of the alphabet, and 3 + 1 + 3 = 7
 * In an in-game view, only 7 Scorpions and Wraiths can be selected at a time.

Cortana Letters and Transmissions

 * There are 14 transmissions. 14 = 7 + 7
 * Cortana signs one letter with seven 'X's and 'O's.
 * Cortana sends seven emails. Alternatively, Letter Three was likely never intended, so seven messages were planned.

I Love Bees
While ilovebees was technically created by 4orty2wo Entertainment rather than Bungie, it is highly probable they were aware of and continued the tradition.
 * When the Apocalypso crashes, all communications in the solar system are disabled for about seven seconds.
 * When players unlocked 777 axons, a voice-actor playing Melissa joined the game.
 * When Kamal Zaman accesses his voice mail, he has seven old messages.
 * Hiro, reading a how-to book on dating, tells Kamal to skip to chapter seven.
 * A part of the game had players guiding the Sleeping Princess out of her "glass coffin", a prison in her mind appearing as a storytale world. Players would have to guide her down various paths marked by signs with unusual markings. The correct paths are Deadly Sins (there are seven), Waves (seven seas), and Skinny Cow and Fat Cow (in the Bible, the Pharoah had a dream about seven skinny cows that ate seven fat cows).
 * When Rani tries to start a chatter business with a friend, their equipment only manages to produce 49. 49 = 7 x 7
 * Rani leaves with 14. 14 = 7 + 7
 * As of 2004, Aunt Margaret has been beekeeping for seven years.
 * Yasmine Zaman's augmentations are preformed in Lab 7.
 * Yasmine Zaman washed out of the Spartan II program at age 14. 14/2=7

Halo: Contact Harvest

 * There were seven space elevators.
 * The UNSC manage to save 250,000 civilians on Harvest: 2+5=7
 * The first space elevator of the Tiara to collapse was the seventh.
 * There were seven small boxes streaking up the Tiara's elevators.
 * Twenty-eight containers were already on the strands in coupled pairs of fourteen. Both 28 and 14 are divisible by 7
 * Every five minutes seven pairs of containers would rise.
 * Later Loki changed the five minute interval for the containers to seven minutes.
 * An ONI report after the Epilogue under <\ CIVILIAN CONTRACTOR "Charlie Hotel" was in brackets [ONI.REF #409871]... 409,871 divided by 58,553 is equal to 7.
 * In that same report can be found 2 other references. The first found in the line SOURCE.REF#JOTUN-s2-05866. 5,866 divided by 838 is 7. And the second is found in the line SOURCE.REF#JOTUN-S4-021147. 21,147 divided by 3,021 is 7. Also, 21 divided by 3 is 7.
 * When Staff Sergeant A.J. Johnson offers his hand to Byrne, he hesitated, enough for Jenkins to count from push-ups 38-45. (45-38=7)

Dates

 * Bungie Day fell on July 7, 2007; or 7/7/07.
 * In the year 117AD John I becomes the 7th Bishop of Jerusalem.
 * The Prophets left their homeworld in the 7th Century BC (648 BC).
 * Most of Halo is set in years beginning with the number 25. 2+5=7

Misc.
"SEVEN summers old Lovely Lyca told; She had wander'd long Hearing the wild birds' song."
 * Seventh Column is the name given to Bungie's official fan club.
 * The Master Chief stands 7' tall.
 * Sangheili stand 8'6" tall. 8+6=14 and 14/2=7
 * The Sangheili name honorific consists of 2 e's. E is the fifth letter of the alphabet. 2+5=7
 * There are seven remaining Spartan-II's still able to fight : John, Fred, Kelly, Linda, and Gray Team, the three missing at the start of the mission to capture a prophet.
 * The Ascii Mister Chief in a Bungie Weekly Update was made with 7s.
 * There are 7 different Covenant races seen in game.
 * In the Halo 2: Original Soundtrack Vol. 1, there are 21 songs. 21=7 &times; 3
 * There are 14 wieldable UNSC weapons in the Halo games and Books. 7 &times; 2=14
 * The Master Chief's number is 117. 1 X 1 X 7 =7
 * It's possible to have 117 extra rounds of certain weapons (MA5C)
 * Smart AIs (such as Cortana) go rampant after seven years of activation.
 * Slipspace has 11 dimensions. The 4 in our universe + 7.
 * Halogens are found in group 7 of the periodic table (possible idea for games name). Element number 117 would theoretically be located in this group.
 * The Tiara has 7 orbital elevators.
 * The Forerunner portal to Installation 00is located on, and all Earth-bound gameplay takes place on the continent of Africa, the shape of which strongly resembles the number 7.
 * Line number 77 in Act III Scene i of Julius Caesar is "Et Tu Brute".
 * There are 7 Halo rings throughout the Halo Series
 * In the credits for Halo 2 and Halo 3 instead of simply using the word "thank" they replace the first letter with a 7, making it "7hank"
 * Including "The Heretic", "Armory" and "Arrival" there are 10 levels in Halo: CE, 15 levels in Halo 2, and 10 levels in Halo 3. 10+15+10=35. 35/5=7.
 * In the Halo: Combat Evolved soundtrack, the total running time is 1:05:08. 1+5+8=14, 14/2=7.
 * "Luck" is a constant thought the novels and games, i.e. "Lucky Number 7"
 * Considering its 10,000 km diameter, Halo would need to rotate at 7 km/s in order to produce artificial Earth-like "gravity" (from centripetal force).
 * In the periodic table, group VII (7), consists of elements known as 'Halogens'.
 * In the Cortana Letters "... In my palace deep, Lyca lies asleep ..." is mentioned on the 7th letter and is believed to be from the poem "The little girl lost-By William Blake". One verse says:

=117=

117 is Master Chief's SPARTAN tag number, but there is more than meets the eye when it comes to this number, including many religious and historical references.

Biblical Reference

 * John-117 is believed by many fans to be a reference to New Testament of the Christian Bible.


 * Bungie Studios is known to have placed many biblical references in their earlier Marathon video game series, and many other such references have been found in the Halo series.


 * Here are passages from the Book of Revelation (more formally known as The Revelation of St. John the Divine). Revelation in Greek is called "The Apocalypse", a title possibly shortened from "The Apocalypse of John."


 * When I saw him, I fell at his feet as though dead. Then he placed his right hand on me and said: “Do not be afraid. I am the First and the Last."
 * I am the Living One; I was dead, and behold I am alive for ever and ever! And I hold the keys of death and Hades.
 * Book of Revelation, NIV. Chapter 1 - verses 17 and 18.


 * And when they shall have finished their testimony, the beast that ascendeth out of the pit shall make war against them, and shall overcome them, and kill them.
 * Revelation. 11:7


 * There are also references in one other book of the Bible. 1 John houses these:


 * But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ cleanses us from all sin.
 * 1 John 1:7 (1 John 1: 7)
 * And the world is passing away, and the lust of it; but he who does the will of God abides forever.
 * - 1 John 2: 1 7


 * And here are passages from the Gospel of John. These are thought less likely to be references:


 * Then after that saith he to his disciples, Let us go into Judaea again.
 * Gospel of John, 11:7


 * For the law was given by Moses, [but] grace and truth came by Jesus Christ.
 * Gospel of John, 1:17

Site 117
Alternatively, others believe the number to be a reference to "Site 117", an archaeological site containing the first evidence of a human battle. The site is near Jebel Sahaba, Nubia and dates from between 12,000-10,000 BC. The site contains 59 human remains of men, women and children who were clearly killed with primitive hunting implements.

117 and 7
Seven has long been a number associated with Bungie. The first three numbers of 76 are 117, the full number being 117649. Also 1*1*7 = 7 and 1+1+7+6+4+9=28 28/4=7.

It is also interesting to note that in the year 117 AD, John I became the 7th Bishop of Jerusalem.

The 7th Halo' Monitor code is 117649. Maybe the 117 is significant because it's the 7th Halo, however the 649 could be significant as well. 9+4-6=7.

The number 819 appears numerous times in the Marathon series. 819/7=117.

Marathon
In Marathon Infinity there was a hidden multiplayer map called Hats Off to 819 (named after fan hamish Sinclair, H=8, S=19) 819 divided by 7 is 117

117 Trivia
In Halo 3, the game won't let you input the tag I-17 or l(lower-case L)-17 saying that these number are reserved. However, it allows J17.

Related Links

 * List of Biblical References in Halo
 * List of Marathon References in Halo