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 A302230 #4 Apr 03 2018 12:20:49 %S A302230 0,1172,9819,105585,2043848,32181643,553097760,9458629708, %T A302230 156841573045,2693021176397,45330956689241,767899918791607, %U A302230 13034126338915675,220281663367352676,3736908224173762193,63270418755935977976 %N A302230 Number of 7Xn 0..1 arrays with every element equal to 1, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302230 Row 7 of A302224. %H A302230 R. H. Hardin, <a href="/A302230/b302230.txt">Table of n, a(n) for n = 1..210</a> %e A302230 Some solutions for n=5 %e A302230 ..0..0..0..1..1. .0..0..0..1..1. .0..0..0..1..1. .0..0..0..1..0 %e A302230 ..0..0..1..0..1. .1..0..1..0..0. .0..0..1..0..1. .0..1..1..0..1 %e A302230 ..1..1..1..0..0. .0..1..1..1..0. .1..1..1..1..0. .0..0..1..0..0 %e A302230 ..0..0..0..1..0. .0..1..0..0..1. .0..0..0..1..0. .0..0..1..1..0 %e A302230 ..0..1..1..0..1. .0..0..1..0..1. .1..1..1..0..1. .0..1..1..0..0 %e A302230 ..0..0..1..0..0. .1..0..1..1..0. .1..0..0..0..1. .0..0..1..1..0 %e A302230 ..0..0..1..1..0. .0..1..0..0..0. .0..1..1..1..1. .0..0..1..0..0 %Y A302230 Cf. A302224. %K A302230 nonn %O A302230 1,2 %A A302230 _R. H. Hardin_, Apr 03 2018