Look and Say

The Look and Say sequence starts with 1 and is continued by looking at each of the runs of the same number in the previous term and combining the length with the original number. For example the next term after 111221 would be 312211 (three ones, two twos and one one).

Print the first 20 terms of the Look and Say sequence.

External links: OEIS A005150, Rosetta Code, Wikipedia