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A001141
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Describe the previous term! (method A - initial term is 5).
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15
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5, 15, 1115, 3115, 132115, 1113122115, 311311222115, 13211321322115, 1113122113121113222115, 31131122211311123113322115, 132113213221133112132123222115
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OFFSET
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1,1
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COMMENTS
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Method A = 'frequency' followed by 'digit'-indication.
a(n+1) - a(n) is divisible by 10^5 for n > 5. - Altug Alkan, Dec 04 2015
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REFERENCES
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S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 452-455.
I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood City, CA, 1991, p. 4.
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LINKS
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EXAMPLE
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The term after 3115 is obtained by saying "one 3, two 1's, one 5", which gives 132115.
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MATHEMATICA
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RunLengthEncode[ x_List ] := (Through[ {First, Length}[ #1 ] ] &) /@ Split[ x ];
LookAndSay[ n_, d_:1 ] := NestList[ Flatten[ Reverse /@ RunLengthEncode[ # ] ] &, {d}, n - 1 ];
F[ n_ ] := LookAndSay[ n, 5 ][ [ n ] ];
Table[ FromDigits[ F[ n ] ], {n, 1, 11} ] (* Zerinvary Lajos, Mar 21 2007 *)
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CROSSREFS
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KEYWORD
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nonn,base,easy,nice
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AUTHOR
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STATUS
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approved
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