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 A212417 #22 Oct 20 2017 14:24:11
%S A212417 1,1,1,3,7,35,135,945,5193,46737
%N A212417 Size of the equivalence class of S_n containing the identity permutation under transformations of positionally adjacent elements of the form abc <--> acb <--> bac where a<b<c.
%H A212417 J. Cassaigne, M. Espie, D. Krob, J.-C. Novelli, F. Hivert, <a href="https://hal.archives-ouvertes.fr/hal-00018547">The Chinese Monoid</a>, Int'l. J. Algebra and Comp. 11 (2001), 301-334.
%H A212417 Z. Hamaker, E. Marberg, B. Pawlowski, <a href="https://arxiv.org/abs/1601.02269">Involution words II: braid relations and atomic structures</a>, arXiv preprint arXiv:1601.02269 [math.CO], 2016. See Remark following Th. 6.18.
%H A212417 S. Linton, J. Propp, T. Roby, and J. West, <a href="http://arxiv.org/abs/1111.3920">Equivalence Classes of Permutations under Various Relations Generated by Constrained Transpositions</a>, arXiv:1111.3920 [math.CO], 2011, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL15/Roby/roby4.html">J. Int. Seq. 15 (2012) #12.9.1</a>
%e A212417 From _Alois P. Heinz_, May 16 2012: (Start)
%e A212417 a(3) = 3: {123, 132, 213}.
%e A212417 a(4) = 7: {1234, 1243, 1324, 1423, 2134, 2143, 2314}. (End)
%Y A212417 Cf. A210667, A210668, A210669, A210671, A212417.
%K A212417 nonn,more
%O A212417 0,4
%A A212417 _Tom Roby_, May 15 2012
%E A212417 a(0)-a(2), a(9) from _Alois P. Heinz_, May 16 2012