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 A370428 #45 Mar 21 2025 07:01:15 %S A370428 1,1,1,4,5,8,12,15,20,24,28,33,39,46,52,58 %N A370428 Connected domination number of the n X n king graph. %C A370428 In other words, a(n) is the minimum number of kings that can be placed on an n X n chessboard such that (i) the occupied squares form a single connected component, and (ii) every square is either occupied by a king or adjacent to one that is. %C A370428 a(17) <= 67; a(18) <= 75; a(19) <= 83; a(20) <= 92. %H A370428 Alexander D. Healy, <a href="/A370428/a370428_4.pdf">Examples of (near-)optimal connected dominating sets for n <= 20</a>. %H A370428 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ConnectedDominationNumber.html">Connected Domination Number</a>. %H A370428 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/KingGraph.html">King Graph</a>. %Y A370428 Cf. A075561, A289180, A302401, A369692. %Y A370428 Cf. A382206 (numbers of minimum connected dominating sets). %K A370428 nonn,more %O A370428 1,4 %A A370428 _Alexander D. Healy_, Feb 24 2024 %E A370428 a(13)-a(16) from _Andrew Howroyd_, Feb 25 2024