The look and say sequence is a sequence of integerse that is defined from the previus sequence by noting how many times an integer is occuring in the prevoius sequence.
For example,  →  →  →  →  →  ...
In the above example 1 is occuring one time giving , the next one is occuring two times giving  and so on.
This is an implementation of the above look and see sequence in python:
#!/usr/bin/env python def las(start,seqs): prev=[start] print prev for i in range(seqs): cnt=0 current= s=prev for j in range(len(prev)): if s==prev[j]: current[cnt]+=1 if(current[cnt]==1): current.append(s) else: s=prev[j] cnt=len(current) current.append(1) current.append(s) print current prev=current