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Describe the previous term! (method A - initial term is 6).
15

%I #31 Aug 30 2023 05:20:56

%S 6,16,1116,3116,132116,1113122116,311311222116,13211321322116,

%T 1113122113121113222116,31131122211311123113322116,

%U 132113213221133112132123222116

%N Describe the previous term! (method A - initial term is 6).

%C Method A = 'frequency' followed by 'digit'-indication.

%C a(n+1) - a(n) is divisible by 10^5 for n > 5. - _Altug Alkan_, Dec 04 2015

%D S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 452-455.

%D I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood City, CA, 1991, p. 4.

%H T. D. Noe, <a href="/A001143/b001143.txt">Table of n, a(n) for n = 1..20</a>

%H J. H. Conway, <a href="http://dx.doi.org/10.1007/978-1-4612-4808-8_53">The weird and wonderful chemistry of audioactive decay</a>, in T. M. Cover and Gopinath, eds., Open Problems in Communication and Computation, Springer, NY 1987, pp. 173-188.

%H S. R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/constant/cnwy/cnwy.html">Conway's Constant</a>. [Broken link]

%H S. R. Finch, <a href="http://web.archive.org/web/20010207194413 /http://www.mathsoft.com/asolve/constant/cnwy/cnwy.html">Conway's Constant</a>. [From the Wayback Machine]

%e The term after 3116 is obtained by saying "one 3, two 1's, one 6", which gives 132116.

%t RunLengthEncode[ x_List ] := (Through[ {First, Length}[ #1 ] ] &) /@ Split[ x ]; LookAndSay[ n_, d_:1 ] := NestList[ Flatten[ Reverse /@ RunLengthEncode[ # ] ] &, {d}, n - 1 ]; F[ n_ ] := LookAndSay[ n, 6 ][ [ n ] ]; Table[ FromDigits[ F[ n ] ], {n, 1, 11} ] (* _Zerinvary Lajos_, Mar 21 2007 *)

%Y Cf. A001155, A005150, A006751, A006715, A001140, A001141, A001145, A001151, A001154.

%K nonn,base,easy,nice

%O 1,1

%A _N. J. A. Sloane_