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 A088203 Infinite audioactive word that shifts 1 place left under "Look and Say" method A, starting with a(1)=2. 7
 2, 1, 2, 1, 1, 1, 2, 3, 1, 1, 2, 1, 3, 2, 1, 1, 2, 1, 1, 1, 3, 1, 2, 2, 1, 1, 2, 3, 1, 1, 3, 1, 1, 2, 2, 2, 1, 1, 2, 1, 3, 2, 1, 1, 3, 2, 1, 3, 2, 2, 1, 1, 2, 1, 1, 1, 3, 1, 2, 2, 1, 1, 3, 1, 2, 1, 1, 1, 3, 2, 2, 2, 1, 1, 2, 3, 1, 1, 3, 1, 1, 2, 2, 2, 1, 1, 3, 1, 1, 1, 2, 3, 1, 1, 3, 3, 2, 2, 1, 1, 2, 1, 3, 2, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A006751(n) = concatenation of n-th row. - Reinhard Zumkeller, Aug 09 2012 From Jean-Christophe HervĂ©, May 07 2013: (Start) The sequence is obtained continuously by applying the look-and-say rule from seed 2: 2 -> 1,2 -> 1,1,1,2 -> etc. The sequence is then determined by pairs of digits. Terms of even ranks are counts while odd ranks are figures. A225224 and A221646 are from seed 1 and A088204 from seed 3. The present sequence is the concatenation of A006751 (original look-and-say method by blocks) because, with seed 2, all blocks of A006751 begin with 1 or 3 and end with 2 and therefore, there is no possible interaction between blocks after concatenation. (end) REFERENCES 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. LINKS Reinhard Zumkeller, Rows n = 1..25 of triangle, flattened Eric W. Weisstein, MathWorld: Look and Say Sequence Wikipedia, Look-and-say sequence PROG (Haskell)  see Watkins link, p. 3. import Data.List (group) a088203 n k = a088203_tabf !! (n-1) !! (k-1) a088203_row n = a088203_tabf !! (n-1) a088203_tabf = iterate                (concat . map (\xs -> [length xs, head xs]) . group) [2] -- Reinhard Zumkeller, Aug 09 2012 CROSSREFS Cf. A088204, A087282, A005150. Cf. A034002, A005150, A006751 Cf. A225224, A221646 (seed one). Sequence in context: A302790 A140816 A029433 * A205649 A176510 A061342 Adjacent sequences:  A088200 A088201 A088202 * A088204 A088205 A088206 KEYWORD nonn,easy,tabf AUTHOR Paul D. Hanna, Sep 22 2003 STATUS approved

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Last modified September 22 15:16 EDT 2018. Contains 315270 sequences. (Running on oeis4.)