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%I #34 Mar 30 2024 12:15:08
%S 0,0,1,1,2,3,11,38,156,638,2973,13882,67868,338147,1720303,8905996,
%T 46774728,248918004,1340083514,7288922610,40019870539,221582395052,
%U 1236358849827
%N Number of irreducible indecomposable spherical curves with n crossings (only ordinary double points), the circle is oriented, the sphere is not oriented (OU case).
%C Old name was "Prime Gaussian (i.e. only ordinary double points) curves with n crossings."
%C Irreducible means not made disconnected by removal of a vertex (no nugatory crossings).
%C Indecomposable (or prime) means not made disconnected by cutting two distinct lines.
%H J. Betrema, <a href="https://github.com/j2b2/TaitCurves">Tait Curves</a>
%H R. Coquereaux and J.-B. Zuber, <a href="http://arxiv.org/abs/1507.03163">Maps, immersions and permutations</a>, arXiv preprint arXiv:1507.03163 [math.CO], 2015-2016. Also J. Knot Theory Ramifications 25, 1650047 (2016), DOI: <a href="https://doi.org/10.1142/S0218216516500474">10.1142/S0218216516500474</a>
%H C. Ernst, C. Hart, T. Menezes and D. Price, <a href="https://doi.org/10.1142/S0218216521500632">A complete list of minimal diagrams of an oriented alternating knot</a>, J. Knot Theory Ramifications 30, 2150063 (2021). See section 3.1.
%o (C) See the J. Betrema C program in the Tait Curves link.
%Y Cf. A008986, A008987, A008988, A008989, A264759, A264760, A264761.
%K nonn,more
%O 1,5
%A Jean Betrema
%E Edited by _Robert Coquereaux_, Nov 23 2015
%E a(15)-a(16) from _Sean A. Irvine_, Jan 22 2018
%E a(17)-a(23) from _Brendan McKay_, Mar 30 2024