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 A295213 #4 Nov 17 2017 07:26:27 %S A295213 1,1,1,1,2,1,1,4,4,1,1,7,10,7,1,1,14,27,27,14,1,1,31,102,147,102,31,1, %T A295213 1,69,345,916,916,345,69,1,1,155,1162,4938,9536,4938,1162,155,1,1,354, %U A295213 4072,27208,85215,85215,27208,4072,354,1,1,814,14224,152236,775547,1245294 %N A295213 T(n,k)=Number of nXk 0..1 arrays with each 1 horizontally or vertically adjacent to 2 or 3 1s. %C A295213 Table starts %C A295213 .1...1.....1......1........1..........1............1..............1 %C A295213 .1...2.....4......7.......14.........31...........69............155 %C A295213 .1...4....10.....27......102........345.........1162...........4072 %C A295213 .1...7....27....147......916.......4938........27208.........152236 %C A295213 .1..14...102....916.....9536......85215.......775547........7213161 %C A295213 .1..31...345...4938....85215....1245294.....18444470......278238087 %C A295213 .1..69..1162..27208...775547...18444470....444447937....10896495280 %C A295213 .1.155..4072.152236..7213161..278238087..10896495280...436106162865 %C A295213 .1.354.14224.848992.66719868.4170628296.265837272259.17352456088907 %H A295213 R. H. Hardin, <a href="/A295213/b295213.txt">Table of n, a(n) for n = 1..264</a> %F A295213 Empirical for column k: %F A295213 k=1: a(n) = a(n-1) %F A295213 k=2: a(n) = 3*a(n-1) -2*a(n-2) +2*a(n-3) -2*a(n-4) -a(n-5) %F A295213 k=3: [order 12] %F A295213 k=4: [order 28] %F A295213 k=5: [order 78] %e A295213 Some solutions for n=5 k=4 %e A295213 ..1..1..1..0. .0..1..1..1. .1..1..1..0. .1..1..1..0. .1..1..1..1 %e A295213 ..1..0..1..0. .0..1..1..1. .1..1..1..0. .1..1..1..0. .1..0..0..1 %e A295213 ..1..0..1..1. .0..0..0..0. .0..0..1..1. .0..0..0..0. .1..1..1..1 %e A295213 ..1..0..1..1. .0..0..1..1. .1..1..1..1. .0..0..1..1. .1..1..1..1 %e A295213 ..1..1..1..1. .0..0..1..1. .1..1..0..0. .0..0..1..1. .0..0..0..0 %Y A295213 Column 2 is A202973. %K A295213 nonn,tabl %O A295213 1,5 %A A295213 _R. H. Hardin_, Nov 17 2017