There has been a long-standing tradition by Bungie and 343 Industries to insert references to the number 7 into the Halo series. This phenomenon of trying to figure out what is and is not a reference to the number 7 is similar to the 23 enigma, a numerological belief coined by author William S. Burroughs about finding connections to prove the significance of the number 23 in real-life. The name of the dedicated Halo studio 343 Industries, and its namesake 343 Guilty Spark, are just two examples of the number 7's prominence in the series, as 343 can be derived from 7 in a few different ways:

7x7=49
49x7=343

7x7x7=343

3+4+3=10
10-3=7