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 A264760 #26 Mar 30 2024 12:15:20 %S A264760 0,0,1,1,2,4,12,41,161,658,2993,13974,67945,338644,1720544,8908579, %T A264760 46775073,248932094,1340079951,7289000415,40019815872,221582832331, %U A264760 123635832467 %N A264760 Number of irreducible indecomposable spherical curves with n crossings (only ordinary double points), the circle is not oriented, the sphere is oriented (UO case). %C A264760 Irreducible means not made disconnected by removal of a vertex (no nugatory crossings). %C A264760 Indecomposable (or prime) means not made disconnected by cutting two disjoint lines. %H A264760 J. Betrema, <a href="https://github.com/j2b2/TaitCurves">Tait Curves</a> %H A264760 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: http://dx.doi.org/10.1142/S0218216516500474 %H A264760 Gunnar Brinkmann and Brendan McKay, <a href="https://users.cecs.anu.edu.au/~bdm/plantri/">plantri plane graph generator</a>. To obtain this sequence use options -Guoqc2m2d (which makes plane quartic graphs) and count those for which the straight-ahead Eulerian walk has a single component. %o A264760 (C) See the J. Betrema C program in the Tait Curves link. %Y A264760 Cf. A008986, A008987, A008988, A008989, A007756, A264759, A264761. %K A264760 nonn,more %O A264760 1,5 %A A264760 _Robert Coquereaux_, Nov 23 2015 %E A264760 a(14)-a(21) from _Brendan McKay_, Mar 12 2023 %E A264760 plantri link added by _Brendan McKay_, Mar 25 2024 %E A264760 a(22) and a(23) from _Brendan McKay_, Mar 30 2024