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 A014377 #47 Feb 16 2025 08:32:33 %S A014377 1,0,0,0,1,5,1547,21609301,733351105934,42700033549946250, %T A014377 4073194598236125132578,613969628444792223002008202, %U A014377 141515621596238755266884806115631 %N A014377 Number of connected regular graphs of degree 7 with 2n nodes. %D A014377 CRC Handbook of Combinatorial Designs, 1996, p. 648. %D A014377 I. A. Faradzev, Constructive enumeration of combinatorial objects, pp. 131-135 of Problèmes combinatoires et théorie des graphes (Orsay, 9-13 Juillet 1976). Colloq. Internat. du C.N.R.S., No. 260, Centre Nat. Recherche Scient., Paris, 1978. %H A014377 Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/C_k-reg_girth_ge_g_index">Index of sequences counting connected k-regular simple graphs with girth at least g</a> %H A014377 M. Meringer, <a href="http://www.mathe2.uni-bayreuth.de/markus/reggraphs.html">Tables of Regular Graphs</a> %H A014377 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RegularGraph.html">Regular Graph</a> %H A014377 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SepticGraph.html">Septic Graph</a> %F A014377 a(n) = A184973(n) + A181153(n). %F A014377 a(n) = A165628(n) - A165877(n). %F A014377 This sequence is the inverse Euler transformation of A165628. %e A014377 a(0)=1 because the null graph (with no vertices) is vacuously 7-regular and connected. %Y A014377 Contribution (almost all) from _Jason Kimberley_, Feb 10 2011: (Start) %Y A014377 7-regular simple graphs: this sequence (connected), A165877 (disconnected), A165628 (not necessarily connected). %Y A014377 Connected regular simple graphs A005177 (any degree), A068934 (triangular array), specified degree k: A002851 (k=3), A006820 (k=4), A006821 (k=5), A006822 (k=6), this sequence (k=7), A014378 (k=8), A014381 (k=9), A014382 (k=10), A014384 (k=11). %Y A014377 Connected 7-regular simple graphs with girth at least g: this sequence (g=3), A181153 (g=4). %Y A014377 Connected 7-regular simple graphs with girth exactly g: A184963 (g=3), A184964 (g=4), A184965 (g=5). (End) %K A014377 nonn,nice,hard,more %O A014377 0,6 %A A014377 _N. J. A. Sloane_ %E A014377 Added another term from Meringer's page. _Dmitry Kamenetsky_, Jul 28 2009 %E A014377 Term a(8) (on Meringer's page) was found from running Meringer's GENREG for 325 processor days at U. Newcastle by _Jason Kimberley_, Oct 02 2009 %E A014377 a(9)-a(11) from _Andrew Howroyd_, Mar 13 2020 %E A014377 a(12) from _Andrew Howroyd_, May 19 2020