23

The number 23 is used in Discordianism, by the Church of the SubGenius, and in The Illuminatus! Trilogy. It is used to represent the unknown, an occult organising system or sign within an organising system, or a sign of a conspiracy.
the earliest use of the code in this way is William Burroughs seminal text Academy 23
In the trilogy, 23 is used as an organising method also by The KLF - for example in their 23 year moratorium which ended in 2017 and also in their book 2023 see 2023: A Trilogy which reuses various figures from the Illuminatus Trilogy such as FUCKUP which they slightly alter to FUUCKUP.