#!/usr/bin/env python "Example how to program in Python via Regexp" import re def Look_and_Say(n): "Produce next element of John Horton Conway's Look-and-say sequence" groups=re.findall(r"((.)\2*)",str(n)) # (aaa, a), (bb, b) ... pairs=["%d%s"%(len(a[0]),a[1]) for a in groups] # 3a, 2b, ... return int("".join(pairs)) # 3a2b... k=1 print 1,k for i in range(2,11): k=Look_and_Say(k) print i,k