Look and say sequence

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Joseph Malkevitch
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Joined: Tue Aug 28, 2007 2:52 pm
Location: Jamaica, New York

Look and say sequence

Postby Joseph Malkevitch » Thu Jan 11, 2018 5:23 pm

Dear Colleagues,

Often to illustrate the issue of looking for patterns one will ask for what is the next number in a given sequence:

1, 3, 5, 7, 9, What is next?

1, 4, 9, 16, 25, What is next?

However, there are many vary exotic examples of sequences, one of the more intriguing being the "look and say" sequence that has been discussed by John Horton Conway.

Given 1, describe this as: one one and you write down:


The above can be described as two ones and you write down


This can be described as one two one one

Continuing on we get the sequence:

1, 11, 21, 1211, 111221, etc.

If you are seeing this for the first time you may not know what comes next in the sequence.

For more information,look at:




Joseph Malkevitch
Department of Mathematics
York College (CUNY)
Jamaica, New York 11451



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