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Search: id:A121808
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| A121808 |
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Say what you see in previous term, reporting each digit encountered followed by frequency. |
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+0
1
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| 1, 11, 12, 1121, 1321, 122131, 132231, 122232, 112431, 13213141, 14213241, 13223142, 12233241, 12233241, 12233241, 12233241, 12233241, 12233241, 12233241, 12233241, 12233241, 12233241
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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Constant at 12233241 after 13 terms.
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EXAMPLE
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To get the term after 13213141, we say: four 1's, one 2, two 3's, one 4; therefore 14213241 (digit named before frequency).
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MATHEMATICA
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RunLengthEncode[ x_List ] := (Through[ {First, Length}[ #1 ] ] &) /@ Split@ Sort@x; LookAndSay[ n_, d_:1 ] := NestList[ Flatten[ Reverse /@ RunLengthEncode[ # ] ] &, {d}, n - 1 ]; F[ n_ ] := LookAndSay[ n, 1 ][ [ n ] ]; Table[ FromDigits[ F[ n ] ], {n, 1, 15} ] (* Robert G. Wilson v Sep 11 2006 *)
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CROSSREFS
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Another variant of A005150, A005151, A063850, etc.
Sequence in context: A056684 A042731 A087304 this_sequence A160265 A007651 A022481
Adjacent sequences: A121805 A121806 A121807 this_sequence A121809 A121810 A121811
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KEYWORD
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base,easy,nonn
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AUTHOR
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Ross Presser (rpresser(AT)gmail.com), Sep 09 2006
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