%I A001140
%S A001140 4,14,1114,3114,132114,1113122114,311311222114,13211321322114,
%T A001140 1113122113121113222114,31131122211311123113322114,
%U A001140 132113213221133112132123222114
%N A001140 Describe the previous term! (method A - initial term is 4).
%C A001140 Method A = 'frequency' followed by 'digit'-indication.
%D A001140 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.
%D A001140 S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 452-455.
%D A001140 I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood 
               City, CA, 1991, p. 4.
%H A001140 S. R. Finch, <a href="http://algo.inria.fr/bsolve/constant/cnwy/cnwy.html">
               Conway's Constant</a>
%e A001140 E.g. the term after 3114 is obtained by saying "one 3, two 1's, one 4", 
               which gives 132114.
%t A001140 RunLengthEncode[ x_List ] := (Through[ {First, Length}[ #1 ] ] &) /@ 
               Split[ x ]; LookAndSay[ n_, d_:1 ] := NestList[ Flatten[ Reverse 
               /@ RunLengthEncode[ # ] ] &, {d}, n - 1 ]; F[ n_ ] := LookAndSay[ 
               n, 4 ][ [ n ] ]; Table[ FromDigits[ F[ n ] ], {n, 1, 11} ] - Zerinvary 
               Lajos (zerinvarylajos(AT)yahoo.com), Mar 21 2007
%Y A001140 Cf. A001155, A005150, A006751, A006715, A001141, A001143, A001145, A001151, 
               A001154.
%Y A001140 Sequence in context: A003010 A118770 A112514 this_sequence A138488 A022508 
               A161741
%Y A001140 Adjacent sequences: A001137 A001138 A001139 this_sequence A001141 A001142 
               A001143
%K A001140 nonn,base,easy,nice
%O A001140 1,1
%A A001140 N. J. A. Sloane (njas(AT)research.att.com).