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 A361135 #33 Mar 21 2023 05:29:16 %S A361135 1,3,8,30,118,548,2790,16029,101353,706572,5375249,44402094,395734706, %T A361135 3786401086,38711834576,421217184135,4860174299186,59278045511959, %U A361135 762055884150141,10299293881159294,145994591873294780,2165938721141964179,33564939201581495090,542344644703485899950,9122110321170144880053 %N A361135 The number of unlabeled connected fairly 4-regular multigraphs of order n, loops allowed. %C A361135 Edges are undirected, vertices not labeled. "Fairly" means that each vertex has degree 4, but two of these edges do not connect to a second vertex; they are "fins" in CAD speak or "half-edges" in perturbation theory. The two fins may be attached to the same or to two different nodes. In the usual mathematical nomenclature these are connected graphs of order n+2 with two vertices of degree 1 and n vertices of degree 4, loops allowed. %H A361135 H. Kleinert, A. Pelster, B. Kastening, and M. Bachmann, <a href="https://doi.org/10.1103/PhysRevE.62.1537">Recursive graphical construction of Feynman diagrams and their multiplicities in Phi^4 and Phi^2*A theory</a>, Phys. Rev. E 62 (2) (2000), 1537 Table II. %H A361135 R. J. Mathar, <a href="/A361135/a361135.pdf">Illustrations</a> %Y A361135 Cf. A085549 (4-regular), A352174 (assuming rooted external legs). %K A361135 nonn,hard %O A361135 1,2 %A A361135 _R. J. Mathar_, Mar 02 2023 %E A361135 Terms a(7) and beyond from _Andrew Howroyd_, Mar 05 2023