This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A343180 #8 May 02 2021 11:39:32 %S A343180 1,2,3,2,1,4,3,2,1,2,3,4,1,4,3,2,1,2,3,2,1,4,3,4,1,2,3,4,1,4,3,2,1,2, %T A343180 3,2,1,4,3,2,1,2,3,4,1,4,3,4,1,2,3,2,1,4,3,4,1,2,3,4,1,4,3,2,1,2,3,2, %U A343180 1,4,3,2,1,2,3,4,1,4,3,2,1,2,3,2,1,4,3,4,1,2,3,4,1,4,3 %N A343180 Trajectory of 1 under the morphism 1 -> 12, 2 -> 32, 3 -> 14, 4 -> 34. %H A343180 J.-P. Allouche and M. Mendes France, <a href="https://webusers.imj-prg.fr/~jean-paul.allouche/allmendeshouches.pdf">Automata and Automatic Sequences</a>, in: Axel F. and Gratias D. (eds), Beyond Quasicrystals. Centre de Physique des Houches, vol 3. Springer, Berlin, Heidelberg, pp. 293-367, 1995; DOI https://doi.org/10.1007/978-3-662-03130-8_11. See page 6. %H A343180 J.-P. Allouche and M. Mendes France, <a href="/A003842/a003842.pdf">Automata and Automatic Sequences</a>, in: Axel F. and Gratias D. (eds), Beyond Quasicrystals. Centre de Physique des Houches, vol 3. Springer, Berlin, Heidelberg, pp. 293-367, 1995; DOI https://doi.org/10.1007/978-3-662-03130-8_11. See page 6. [Local copy] %p A343180 f(1):= (1,2): f(2):= (3,2): f(3) := (1,4); f(4) := (3,4); # %p A343180 A:= [1]: %p A343180 for i from 1 to 8 do A:= map(f, A) od: %p A343180 A; %Y A343180 A112658 is another version of the same sequence. %K A343180 nonn %O A343180 0,2 %A A343180 _N. J. A. Sloane_, May 02 2021