"Cuckoss's Egg" sequence, next number? In The cuckoo's Egg by Cliff Stoll, an astronomer at Berkeley Lab and then at Harvard, who had discovered that hacker's infiltrated his computer--and of the military government. He was very good at understanding the hacker at at time when the goverment had never considered this possibility. He records a conversation with a friend at National Security Lab: "OTTFFSS, what's the next letter Cliff?" This was an oldie. "One, Two, Three....the next letter is E for eight." "Complete the series Cliff: 1, 11, 21, 1211, 111221..." Cliff adds, "I looked at it for five minutes and gave up. To this day, I still haven't solved it." I really wonder about that series, does anyone see how it goes?