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Cuckoss's Egg sequence, next number?

  1. Nov 8, 2004 #1
    "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?
    Last edited: Nov 8, 2004
  2. jcsd
  3. Nov 8, 2004 #2


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    Yes, this puzzle has been posted here before :

    In white Each new number tells the digits that occur in the previous number, in terms of their repetitions. Let me transcribe the existing series :

    [ start with 1=ONE ]
    11=one ONE
    21=two ONEs
    1211=one TWO, one ONE
    111221=one ONE, one TWO & two ONEs

    the next line must describe this last line, which has "three ONEs, two TWOs, & one ONE = 312211
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