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 A221373 A two-digit Look-and-Say sequence starting with 99: each term summarizes the increasing two-digit substrings of the previous term. 6
 99, 199, 119199, 111219191199, 311112319121291199, 411312219121123129231291199, 311512113219221122223229331141291192199, 511312113114115319421522123229231232133141151191292193199, 611412313214315419521222323229631232133241142251152153191292193194199 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(22) is the first term containing a zero; this is due to the fact that a(21) is the first term having exactly 10 occurrences of a two-digit number, namely 10 x 32. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..1000 Eric Weisstein's World of Mathematics, Look and Say Sequence Wikipedia, Look-and-say sequence Reinhard Zumkeller, Haskell program for two-digit Look-and-Say sequences EXAMPLE a(0) = 11: 1x99 --> a(1)=199; a(1) = 199: 1x19 and 1x99 --> a(2)=119199; a(2) = 119199: 1x11, 2x19, 1x91 and 1x99 --> a(3)=111219191199; a(3) = 111219191199: 3x11, 1x12, 3x19, 1x21, 2x91 and 1x99 --> a(4)=311112319121291199. PROG (Haskell) See Link. CROSSREFS Cf. A005151, A047842. Cf. A209234 (start=10), A209233 (start=11), A221368 (start=12), A221369 (start=13), A221372 (start=19). Sequence in context: A031500 A044431 A044812 * A260242 A250734 A260279 Adjacent sequences: A221370 A221371 A221372 * A221374 A221375 A221376 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, Jan 13 2013 STATUS approved

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Last modified October 4 12:37 EDT 2023. Contains 365876 sequences. (Running on oeis4.)