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%I #10 Apr 24 2024 12:30:18
%S 19,119,111119,411119,311119141,311114119131141191,
%T 611113214219231241291,
%U 311212113114119221123124129131132141142161191192,911512313314116319521122123124129431132341142161291292
%N A two-digit Look-and-Say sequence starting with 19: each term summarizes the increasing two-digit substrings of the previous term.
%C a(16) is the first term containing a zero; this is due to the fact that a(15) is the first term having exactly 10 occurrences of a two-digit number, namely 10 x 51.
%H Reinhard Zumkeller, <a href="/A221372/b221372.txt">Table of n, a(n) for n = 0..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/LookandSaySequence.html">Look and Say Sequence</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Look-and-say_sequence">Look-and-say sequence</a>
%H Reinhard Zumkeller, <a href="/A209234/a209234.hs.txt">Haskell program for two-digit Look-and-Say sequences</a>
%e a(0) = 19: 1 x 19 --> a(1) = 119;
%e a(1) = 119: 1 x 11 and 1 x 19 --> a(2) = 111119;
%e a(2) = 111119: 4 x 11 and 1 x 19 --> a(3) = 411119;
%e a(3) = 411119: 3 x 11, 1 x 19 and 1 x 41 --> a(4) = 311119141.
%o (Haskell) -- See Link.
%Y Cf. A005151, A047842.
%Y Cf. A209234 (start=10), A209233 (start=11), A221368 (start=12), A221369 (start=13), A221373 (start=99).
%K nonn,base
%O 0,1
%A _Reinhard Zumkeller_, Jan 13 2013