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%I #5 Aug 05 2018 10:04:32
%S 2,13,121,121312,12131211213,12131211213121213121,
%T 1213121121312121312112131213121121312,
%U 12131211213121213121121312131211213121213121121312112131212131211213
%N a(n) = concatenation of n-th stage of the trajectory of 2 under the tribonacci morphism 1 -> {1, 2}, 2 -> {1, 3}, 3 -> {1}.
%C a(n) is the concatenation of A103269(n-1) and A103269(n-2) for n >= 2.
%H Bo Tan and Zhi-Ying Wen, <a href="http://dx.doi.org/10.1016/j.ejc.2006.07.007">Some properties of the Tribonacci sequence</a>, European Journal of Combinatorics, 28 (2007) 1703-1719. See B_n.
%Y Cf. A103269.
%K nonn
%O 0,1
%A _N. J. A. Sloane_, Aug 05 2018