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Look-and-Say Sequence


Date: 02/14/2002 at 17:57:44
From: Vanessa
Subject: Find the 6 missing numbers in number sequences

I can't figure the answer out. I can't seem to find the next six 
numbers..
 
 1,11,21,1211,111221,_,_,_,_,_,_.

Thanks.


Date: 02/15/2002 at 12:21:02
From: Doctor Douglas
Subject: Re: Find the 6 missing numbers in number sequences

Hi, Vanessa, and thanks for writing.

This is a famous sequence known as the "look-and-say" sequence. You 
can probably figure out how the whole sequence works just from that 
hint alone (try it!).

You can find out lots more interesting information about this and 
closely related sequences at the following sites:

  121, 111211, 311221 Puzzle
  http://mathforum.org/dr.math/problems/joey.10.23.01.html   

  Look and Say Sequence: MathWorld - Eric Weisstein
  http://mathworld.wolfram.com/LookandSaySequence.html   

  Conway's Constant - Steven Finch
  http://pauillac.inria.fr/algo/bsolve/constant/cnwy/cnwy.html   

  Conway Sequence - Torsten Sillke
  http://www.mathematik.uni-bielefeld.de/~sillke/SEQUENCES/series000   

I hope this helps.

- Doctor Douglas, The Math Forum
  http://mathforum.org/dr.math/   
    
Associated Topics:
High School Puzzles
High School Sequences, Series
Middle School Puzzles

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