What is a Sequence - Definition & Examples

Dave and Andy's is a popular local ice-cream shop. In addition to selling ice-cream by the scoop as well as milkshakes, they also sell packed pints and quarts in the summer. The following are numbers of packed pints and quarts they sold the first few days of June: $$2, 5, 8, 11, 14, 17$$ Does it follow a pattern? What is it?