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 A006715 Describe the previous term! (method A - initial term is 3). (Formerly M2965) 26
 3, 13, 1113, 3113, 132113, 1113122113, 311311222113, 13211321322113, 1113122113121113222113, 31131122211311123113322113, 132113213221133112132123222113, 11131221131211132221232112111312111213322113, 31131122211311123113321112131221123113111231121123222113 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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 REFERENCES 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. LINKS T. D. Noe, Table of n, a(n) for n=1..20 Éric Brier, Rémi Géraud-Stewart, David Naccache, Alessandro Pacco, and Emanuele Troiani, Stuttering Conway Sequences Are Still Conway Sequences, arXiv:2006.06837 [math.DS], 2020. Éric Brier, Rémi Géraud-Stewart, David Naccache, Alessandro Pacco, and Emanuele Troiani, The Look-and-Say The Biggest Sequence Eventually Cycles, arXiv:2006.07246 [math.DS], 2020. 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, Conway's Constant [Broken link] S. R. Finch, Conway's Constant [From the Wayback Machine] Eric W. Weisstein, MathWorld: Look and Say Sequence. EXAMPLE The term after 3113 is obtained by saying "one 3, two 1's, one 3", which gives 132113. 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, 3 ][ [ n ] ]; Table[ FromDigits[ F[ n ] ], {n, 11} ] (* Zerinvary Lajos, Mar 21 2007 *) PROG (Perl) # This outputs the first n elements of the sequence, where n is given on the command line. \$s = 3; for (2..shift @ARGV) {     print "\$s, ";     \$s =~ s/(.)\1*/(length \$&).\$1/eg; } print "\$s\n"; ## Arne 'Timwi' Heizmann (timwi(AT)gmx.net), Mar 12 2008) CROSSREFS Cf. A001140, A001141, A001143, A001145, A001151, A001154, A001155, A005150, A006751. Cf. A088204 (continuous version). Sequence in context: A073428 A118628 A112513 * A177362 A138487 A022507 Adjacent sequences:  A006712 A006713 A006714 * A006716 A006717 A006718 KEYWORD nonn,base,easy,nice AUTHOR STATUS approved

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Last modified November 28 09:10 EST 2020. Contains 338703 sequences. (Running on oeis4.)