111221

111221 is the fifth term of the look-and-say sequence when the initial term is 1. It is formed by describing the previous term, 1211, as "one 1, one 2, two 1s," which yields 111221.

In the look-and-say sequence, each term is generated by reading off the digits of the previous term in groups of identical digits and writing the counts followed by the digit itself. Starting with 1, the sequence goes 1, 11, 21, 1211, 111221, 312211, 13112221, and so on.

111221 is a six-digit number that uses only the digits 1 and 2. The subsequent term is 312211, obtained by describing 111221 as "three 1s, two 2s, one 1."

As part of the standard look-and-say sequence, 111221 is often cited in mathematical discussions of recursive digit-replacement processes. In the theory developed by John Conway, the sequence exhibits long-term behavior where terms evolve toward a finite set of components and grow in length by a constant factor known as Conway's constant, approximately 1.303577... per step.