In mathematics, the look-and-say sequence is the sequence of integers beginning as follows: 1, 11, 21, 1211, 111221, 312211, 13112221, 1113213211, ... (sequence A005150 in the OEIS). To generate a member of the sequence from the previous member, read off the digits of the previous member...
The Look and say sequence is a recursively defined sequence of numbers studied most notably by John Conway. Sequence Definition. Take a decimal number. Look at the number, visually grouping consecutive runs of the same digit.