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A005341
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Length of n-th term in Look and Say sequence A005150.
(Formerly M0321)
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6
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1, 2, 2, 4, 6, 6, 8, 10, 14, 20, 26, 34, 46, 62, 78, 102, 134, 176, 226, 302, 408, 528, 678, 904, 1182, 1540, 2012, 2606, 3410, 4462, 5808, 7586, 9898, 12884, 16774, 21890, 28528, 37158, 48410, 63138, 82350, 107312, 139984, 182376, 237746, 310036, 403966, 526646, 686646
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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REFERENCES
| J. H. Conway, The weird and wonderful chemistry of audioactive decay, in T. M. Cover and Gopinath, eds., Open Problems in Communication and Communications, 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).
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LINKS
| S. R. Finch, Conway's Constant
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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FORMULA
| Satisfies a recurrence of order 71.
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MATHEMATICA
| RunLengthEncode[ x_List ] := (Through[ {First, Length}[ #1 ] ] &) /@ Split[ x ]; LookAndSay[ n_, d_:1 ] := NestList[ Flatten[ Reverse /@ RunLengthEncode[ # ] ] &, {d}, n - 1 ]; F[ n_ ] := LookAndSay[ n, 1 ][ [ n ] ]; Table[ Length[ F[ n ] ], {n, 1, 51} ]
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PROG
| (PARI) print1(a=1); for(i=2, 100, print1(", ", #Str(a=A005150(2, a)))) \\ - M. F. Hasler, Nov 08 2011
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CROSSREFS
| Sequence in context: A178883 A109832 A039731 * A137268 A008130 A055388
Adjacent sequences: A005338 A005339 A005340 * A005342 A005343 A005344
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KEYWORD
| nonn,base,easy,nice
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AUTHOR
| Jeffrey Shallit
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EXTENSIONS
| More terms from Mike Keith (Domnei(AT)aol.com)
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