The number 737 is a numeric symbol used by Public Enemy Number 1 (PENI), a California-based white supremacist gang present on California's streets and in its prisons. The numbers 737 correspond to the letters P, D, and S on a telephone keypad; the initials PDS stand for Peni Death Squad, another name for the group.
The number combination 14/23 is a numeric symbol associated with the Southern Brotherhood, the largest white supremacist prison gang in Alabama. The 14 is a reference to the white supremacist "14 Words" slogan ("We must secure the existence of our people and a future for white children"), while the 23 refers to the "23 precepts," a list of rules that Southern Brotherhood members must follow.
The number combination 23/16 is a numeric symbol used by white supremacists, particularly common on the West Coast. Substituting letters for numbers, the 23/16 equates to W/P or "White Power." Sometimes the combination is rendered as 16/23, in which case it is often intended to mean P/W for "peckerwood."