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A006715
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Describe the previous term! (method A - initial term is 3).
(Formerly M2965)
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24
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3, 13, 1113, 3113, 132113, 1113122113, 311311222113, 13211321322113, 1113122113121113222113, 31131122211311123113322113, 132113213221133112132123222113
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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.
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REFERENCES
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J. H. Conway, The weird and wonderful chemistry of audioactive decay, in T. M. Cover and Gopinath, eds., Open Problems in Communication and Computation, Springer, NY 1987, pp. 173-188.
S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 452-455.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood City, CA, 1991, p. 4.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..20
S. R. Finch, Conway's Constant
Eric W. Weisstein, MathWorld: Look and Say Sequence.
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EXAMPLE
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The term after 3113 is obtained by saying "one 3, two 1's, one 3", which gives 132113.
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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, 3 ][ [ n ] ]; Table[ FromDigits[ F[ n ] ], {n, 1, 11} ] (* Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 21 2007 *)
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CROSSREFS
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Cf. A001155, A005150, A006751, A001140, A001141, A001143, A001145, A001151, A001154.
Cf. A088204 (continuous version).
Sequence in context: A073428 A118628 A112513 * A177362 A138487 A022507
Adjacent sequences: A006712 A006713 A006714 * A006716 A006717 A006718
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KEYWORD
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nonn,base,easy,nice
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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