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 A289709 #20 Feb 16 2025 08:33:49
%S A289709 2,4,10,28,84,272,946,3486,13560,55432,236852,1054928,4881972,
%T A289709 23420436,116204016,595246848,3142169416,17068245184,95267426432,
%U A289709 545732236936,3204607199704
%N A289709 Number of independent vertex sets and vertex covers in the n-triangular honeycomb queen graph.
%H A289709 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/IndependentVertexSet.html">Independent Vertex Set</a>
%H A289709 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/VertexCover.html">Vertex Cover</a>
%F A289709 From _Andrew Howroyd_, Sep 12 2019: (Start)
%F A289709 a(n) = 6*A283117(n) - 2*A326611(n) - 3*2^ceiling(n/2).
%F A289709 a(n) = 1 + Sum_{k>=1} A193986(n,k).
%F A289709 (End)
%Y A289709 Cf. A193986, A283117, A289883, A289893, A326611.
%K A289709 nonn,more
%O A289709 1,1
%A A289709 _Eric W. Weisstein_, Jul 14 2017
%E A289709 a(13)-a(21) from _Andrew Howroyd_, Sep 12 2019