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 A177555 #14 Mar 11 2021 20:42:48 %S A177555 1,1,6,67,1345,42540,1954681,123179785,10202958366,1075213876195, %T A177555 140503060278001,22298495343474372,4224949686497139601, %U A177555 942067522308032112721,244201603555824428994486,72820161285112813781838787,24752401241200431437146873345 %N A177555 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up. %H A177555 Mingjia Yang, Doron Zeilberger, <a href="https://arxiv.org/abs/1805.06077">Increasing Consecutive Patterns in Words</a>, arXiv:1805.06077 [math.CO], 2018. %H A177555 Mingjia Yang, <a href="https://doi.org/10.7282/t3-d9z1-aw94">An experimental walk in patterns, partitions, and words</a>, Ph. D. Dissertation, Rutgers University (2020). %K A177555 nonn %O A177555 0,3 %A A177555 _R. H. Hardin_, May 10 2010 %E A177555 a(12)-a(15) from _Alois P. Heinz_, Oct 22 2013 %E A177555 a(0), a(16) from _Alois P. Heinz_, Aug 08 2018