Correct Answer: It is a strange sequence Each number describes the resemblance of the previous one, except the first one 11 describes the previous '1' which contains one '1' 21 describes the previous '11' which contains two '1' 1211 describes the previous '21' which contains one '2' and one '1' 111221 describes the previous '1211' which contains one '1', one '2' and two '1' So the next sequence will be 312211, that is the previous '111221' contains three '1', two '2' and one '1'