2013 Green Sequence is a free theme for WordPress created by Joen A..
Green color scheme for Twenty Thirteen, alternates colors sequentially instead of per post formats.
(Description "2013 Green Sequence" Theme from wordpress.org)
You can download 2013 Green Sequence for free via the provided download link and include it into your themes folder of your WordPress installation. Also you can directly search for it in the WordPress admin interface in the themes section and install and activate it from there.
More information, screenshots and reviews of 2013 Green Sequence Theme can be found here.