Math Solutions: Web page developed by Marilyn Burns. Free lessons, articles, and more.
Mathwire is an excellent site for standards-based math activities. Find links to growing pattern lessons here.
Illuminations is NCTM's site for classroom lesson plans as well as online activities. You'll find everything organized by strand as well as grade level.
This is a link to math learning center ideas for Pre-K & K that focus on growing patterns. The centers are linked to literature and music.