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find the next number in the sequence

1,11,21,1112,3112,211213,...

think about all of the numbers and the number after it

it is not 311223

you need think outside the box

this is not a math question

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    $\begingroup$ Does this answer your question? Interview Question or Pathbreaking puzzle (Just the numbers have been rearranged slightly to use a numeric order, but they are essentially the same premise...) $\endgroup$ – Stiv Jul 7 '20 at 20:42
  • $\begingroup$ OEIS: oeis.org/A005151 Also note that it is a variant of the much better known Look and Say sequence with the digits being counted arranged in ascending order. The Look and Say sequence's general term is based on how the previous term is arranged. OEIS: oeis.org/A005150 $\endgroup$ – Deepak Jul 8 '20 at 14:14
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1 has $1$ one, so 11.
11 has $2$ ones, so 21.

You do this until you get

211213.
Now, 211213 has $3$ ones, $2$ twos and $1$ three.

So the answer is

312213

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