Hi, what do you want to do?
Khan Academy
Khan Academy: Converting Recursive and Explicit Forms of Arithmetic Sequences
Given the explicit formula of an arithmetic sequence, find its recursive formula, and vice versa. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Mathigon
Mathigon: Algebra: Arithmetic and Geometric Sequences
This lesson focuses on arithmetic and geometric sequences using several examples and practice exercises.