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 A165878 #20 Feb 16 2025 08:33:11 %S A165878 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,7,100,10901,3470736, %T A165878 1473822243,734843169811,423929978716908,281768931380519766, %U A165878 215039290728074333738,187766225244288486398132,186874272297562916477691894,211165081721567703008217979077 %N A165878 Number of disconnected 8-regular simple graphs on n vertices. %H A165878 Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/A068933">Disconnected regular graphs (with girth at least 3)</a> %H A165878 Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/D_k-reg_girth_ge_g_index">Index of sequences counting disconnected k-regular simple graphs with girth at least g</a> %H A165878 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DisconnectedGraph.html">Disconnected Graph</a> %H A165878 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/OcticGraph.html">Octic Graph</a> %F A165878 a = A180260 - A014378 = Euler_transformation(A014378) - A014378. %F A165878 a(n) = D(n, 8) in the triangle A068933. %e A165878 The a(18)=1 graph is K_9+K_9. %Y A165878 8-regular simple graphs: A014378 (connected), this sequence (disconnected), A180260 (not necessarily connected). %Y A165878 Disconnected regular simple graphs: A068932 (any degree), A068933 (triangular array), specified degree k: A165652 (k=2), A165653 (k=3), A033483 (k=4), A165655 (k=5), A165656 (k=6), A165877 (k=7), this sequence (k=8), A185293 (k=9), A185203 (k=10), A185213 (k=11). %K A165878 nonn,hard %O A165878 0,21 %A A165878 _Jason Kimberley_, Sep 29 2009 %E A165878 Terms a(26) and beyond from _Andrew Howroyd_, May 20 2020