- Swordquest: Earthworld (Atari 2600) online game (atarionline.org)
SwordQuest: EarthWorld is an action-adventure game released for the Atari 2600 and is part of the SwordQuest series. The gameplay involves navigating through rooms, collecting items, completing action stages to find more items, and discovering sets of numbers when the right combination of items is placed in the right rooms.
- Catalan number (Wikipedia)
In combinatorial mathematics, the Catalan numbers are a sequence of natural numbers that occur in various counting problems, often involving recursively defined objects. They are named after the French-Belgian mathematician Eugène Charles Catalan.