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 A316340 #16 Jun 01 2025 17:31:55
%S A316340 1,2,3,1,2,3,4,1,3,4,1,3,4,1,2,3,1,2,3,4,1,3,4,1,3,4,1,2,3,1,2,3,1,2,
%T A316340 3,4,1,3,4,1,2,3,1,2,3,1,2,3,4,1,3,4,1,2,3,1,2,3,1,2,3,4,1,3,4,1,3,4,
%U A316340 1,2,3,1,2,3,4,1,3,4,1,3,4,1,2,3,1,2,3,1,2,3,4,1,3,4,1,2,3,1,2
%N A316340 Image of 1 under repeated application of the morphism 1 -> 12312, 2 -> 341, 3 -> 34134, 4 -> 123.
%C A316340 Following this with the morphism 1,2 -> 0, 3,4 -> 1 gives A275129.
%H A316340 Jean-Paul Allouche, Julien Cassaigne, Jeffrey Shallit, Luca Q. Zamboni, <a href="https://arxiv.org/abs/1711.10807">A Taxonomy of Morphic Sequences</a>, arXiv preprint arXiv:1711.10807 [cs.FL], Nov 29 2017.
%t A316340 SubstitutionSystem[{1 -> {1,2,3,1,2}, 2 -> {3,4,1}, 3 -> {3,4,1,3,4}, 4 -> {1,2,3}}, {1}, 4] // Last (* _Jean-François Alcover_, Aug 05 2018 *)
%Y A316340 Cf. A275129.
%Y A316340 Sequences mentioned in the Allouche et al. "Taxonomy" paper, listed by example number: 1: A003849, 2: A010060, 3: A010056, 4: A020985 and A020987, 5: A191818, 6: A316340 and A273129, 18: A316341, 19: A030302, 20: A063438, 21: A316342, 22: A316343, 23: A003849 minus its first term, 24: A316344, 25: A316345 and A316824, 26: A020985 and A020987, 27: A316825, 28: A159689, 29: A049320, 30: A003849, 31: A316826, 32: A316827, 33: A316828, 34: A316344, 35: A043529, 36: A316829, 37: A010060.
%K A316340 nonn
%O A316340 0,2
%A A316340 _N. J. A. Sloane_, Jul 14 2018