Maybe you were looking for one of these abbreviations: RCMX-RCN-RCNC-RCNN-RCNO-RCO-AK-RCO-NE-RCoA-RCOCI-RCOE.
Measure the width of your quilt and add 4-6 (or chosen excess). Design a backing to equal that width, adding 1/2 to each panel for each seam you'll use to sew it to a neighboring panel. Cut panels to the length of your quilt plus 4-6 (or chosen excess). Sew panels together with a 1/2 seam allowance. Press seams open to reduce bulk. Press backing before use.
Planning the Quilt Back. You can piece leftover fabrics from the quilt top or from an entirely different quilt project. This is especially charming when you are making a reproduction or historical quilt. Like batting, the backing needs to be larger than the quilt top. This allows for the fabric that is taken up during the quilting and for stabilization when using a quilting frame. Always add 6 to both the length and width measurements so you have an extra 3 all around.