The Standards of the National Council of Teachers of Mathematics emphasizes that patterns are of recurring importance to mathematics. The following is excerpted from the NCTM's Curriculum and Evaluation Standards for School Mathematics.
Patterns are everywhere.
Children who are encouraged to look for patterns and to express them mathematically begin to understand how mathematics applies to the world in which they live. Identifying and working with a wide variety of patterns helps children to develop the ability to classify and organize information. Relating patterns in numbers, geometry, and measurement helps them understand connections among mathematical topics. Such connections foster the kind of mathematical thinking that serves as a foundation for the more abstract ideas studied in later grades. From the earliest grades, the curriculum should give students opportunities to focus on regularities in events, shapes, designs, and sets of numbers.