Math, Recursion, Recurrent Relations, Generating Functions, Discrete Mathematics.
Using generating functions By 克勞棣 — Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=38708516 Recurrence relations, also called recursion, are functions that use previous values to calculate the next one. A famous example is the Fibonacci sequence, The recursive Fibonacci