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%I A278993 #19 Nov 03 2021 06:03:43
%S A278993 0,1,1,4,21,176,1893,25030,382272,6604535,127222636,2702798537,
%T A278993 62778105236,1582725739329,43046433007765,1256332883208474,
%U A278993 39165907107963273,1298945495674093932,45666536827274985585,1696460750775267473762
%N A278993 Number of simple chord diagrams with n chords, up to rotation.
%H A278993 E. Krasko and A. Omelchenko, <a href="http://arxiv.org/abs/1601.05073">Enumeration of Chord Diagrams without Loops and Parallel Chords</a>, arXiv preprint arXiv:1601.05073 [math.CO], 2016.
%H A278993 E. Krasko and A. Omelchenko, <a href="https://doi.org/10.37236/6037">Enumeration of Chord Diagrams without Loops and Parallel Chords</a>, The Electronic Journal of Combinatorics, 24(3) (2017), #P3.43.
%Y A278993 Cf. A003436, A003437, A007474, A278990, A278991, A278992, A278994.
%K A278993 nonn
%O A278993 1,4
%A A278993 _N. J. A. Sloane_, Dec 07 2016

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