Definition
Sequences may be finite or infinite, and their terms may be numbers or functions.
For example, the following is a sequence of Fibbonachi numbers,
\left(1,1,2,3,5,8,13,\dots\right).
We would denote the sequence (F_k)_{k\in \mathbb{N}}, where F_1 = 1, F_2 = 1, F_3 = 2, ect.