the following sequence is formed using words and numbers: • the first number is 1 • in the first number, there was one 1 so the second number is 11 • in the second number, there were two 1s, so the third number is 21 • in the previous number, there was one 2 and there was one 1, so the fourth number is 1211 • the next number is 111221, one 1, one 2, two 1's. 1 >