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 A296946 #7 Feb 25 2019 09:33:11 %S A296946 2,8,16,36,112,256,608,1680,4064,9920,25984,64320,159232,407296, %T A296946 1017344,2536704,6420992,16093184,40271872,101471232,254636032, %U A296946 638328832,1605165056,4029763584,10110525440,25402425344,63780978688,160088997888 %N A296946 Number of n X 2 0..1 arrays with each 1 adjacent to 1, 3 or 5 king-move neighboring 1s. %H A296946 R. H. Hardin, <a href="/A296946/b296946.txt">Table of n, a(n) for n = 1..210</a> %F A296946 Empirical: a(n) = 2*a(n-1) + 8*a(n-3) - 12*a(n-4). %F A296946 Empirical g.f.: 2*x*(1 + 2*x - 6*x^3) / (1 - 2*x - 8*x^3 + 12*x^4). - _Colin Barker_, Feb 25 2019 %e A296946 Some solutions for n=7: %e A296946 ..0..0. .1..1. .1..1. .1..0. .1..1. .1..1. .0..1. .1..1. .0..0. .0..0 %e A296946 ..1..1. .0..0. .0..0. .0..1. .0..0. .0..0. .0..1. .1..1. .0..0. .1..1 %e A296946 ..0..0. .1..1. .0..1. .1..1. .0..1. .1..1. .1..1. .1..1. .0..0. .1..1 %e A296946 ..1..1. .0..0. .0..1. .1..0. .0..1. .1..1. .1..0. .0..0. .1..1. .0..0 %e A296946 ..0..0. .0..0. .0..0. .1..0. .1..1. .0..0. .0..1. .1..1. .1..1. .1..1 %e A296946 ..0..0. .0..1. .0..1. .0..0. .0..1. .0..1. .0..0. .0..0. .0..0. .1..1 %e A296946 ..1..1. .0..1. .1..0. .1..1. .1..0. .1..0. .0..0. .0..0. .1..1. .1..1 %Y A296946 Column 2 of A296952. %K A296946 nonn %O A296946 1,1 %A A296946 _R. H. Hardin_, Dec 22 2017