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I have this pattern:

1 11 21 1211 111221 

I'm guessing it's a fibo pattern, been at it for hours now. Anyone know?

  • 0
    @Vincent Well, yeah. You can never reach some $\dots1111\dots$ , as that would've simplified from the previous number down to $\dots21\dots$.2016-08-31

2 Answers 2

16

It's known as the look-and-say sequence.

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In the first row, there is one 1 (11). In the second, two 1s (21). In the third, there is one 2 then one 1 (1211). In the fourth, there is one 1 then one 2 then two 1s (111221). It continues in this way, so the next row would be 312211.