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 A337495 #7 Sep 24 2020 03:38:44 %S A337495 1,1,1,2,3,4,7,11,16,26,42 %N A337495 Maximum number of preimages that a permutation of length n can have under the consecutive-123-avoiding stack-sorting map. %H A337495 Colin Defant and Kai Zheng, <a href="https://arxiv.org/abs/2008.12297">Stack-sorting with consecutive-pattern-avoiding stacks</a>, arXiv:2008.12297 [math.CO], 2020. %e A337495 The consecutive-123-avoiding stack-sorting map acts on permutations of length 3 by reversing every permutation except 321, which gets sent to 213. The permutation 213 has 2 preimages under this map (namely, 312 and 321), and every other permutation of length 3 has at most one preimage. Hence, a(3)=2. %K A337495 nonn,more %O A337495 0,4 %A A337495 _Colin Defant_, Aug 29 2020