Question

The Challenge

The shortest code by character count that will output the Morris Number Sequence. The Morris Number Sequence, also known as the Look-and-say sequence is a sequence of numbers that starts as follows:

1, 11, 21, 1211, 111221, 312211, ...

You can generate the sequence infinitely (i.e, you don’t have to generate a specific number).

I/O Expectations

The program doesn’t need to take any input (but bonus points for accepting input and thereby providing the option to start from any arbitrary starting point or number). At the very least your program must start from 1.

Output is at the very least expected to be the sequence:

1
11
21
1211
111221
312211
...

Extra Credit

If you’re going for extra credit, you would need to do something like this:

$ morris 1
1
11
21
1211
111221
312211
...

$ morris 3
3
13
1113
3113
132113
...

Answer 1

GolfScript – 41 (extra credit: 40)

1{.p`n+0:c:P;{:|P=c{c`P|:P!}if):c;}%~1}do
{~.p`n+0:c:P;{:|P=c{c`P|:P!}if):c;}%1}do

What?
The procedure for getting the next number in the sequence: Convert the current number to a string, append a newline and loop over the characters. For each digit, if the previous digit P is the same, increment the counter c. Otherwise, add c and P to what will be next number, then update these variables. The newline we append allows the last group of digits to be added to the next number.

The exact details can be obtained examining the GolfScript documentation. (Note that | is used as a variable.)