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 A243391 #21 Dec 03 2024 11:16:54 %S A243391 1,3,4,12,22,68,166,534,1589,5464,18579,68320,255424,1000852,4018156, %T A243391 16671976,70890940,309439942,1381815168,6310880471,29428287639, %U A243391 140012980007,678970863717,3353545264060,16857749613964,86191265140699,447951112379963,2365177154077186 %N A243391 Number of isomorphism classes of connected 3-regular loopless multigraphs with n vertices and with semi-edges allowed. %C A243391 a(n) is also the number of isomorphism classes of connected loopless multigraphs with n vertices of degree 3 or less. - _Andrew Howroyd_, Mar 20 2020 %H A243391 Nino Bašić and Ivan Damnjanović, <a href="https://arxiv.org/abs/2411.16904">On cubic polycirculant nut graphs</a>, arXiv:2411.16904 [math.CO], 2024. See p. 22. %H A243391 Gunnar Brinkmann, Nico Van Cleemput, and Tomaž Pisanski, <a href="http://dx.doi.org/10.1016/j.tcs.2012.01.018">Generation of various classes of trivalent graphs</a>, Theoretical Comp. Sci. (2013) Vol. 502, 16-29. %Y A243391 Column k=3 of A334546. %Y A243391 Cf. A000421, A243392, A243393, A243394, A303030. %K A243391 nonn %O A243391 1,2 %A A243391 _Nico Van Cleemput_, Jun 04 2014 %E A243391 a(23)-a(28) from _Andrew Howroyd_, Mar 20 2020