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 A298256 #4 Jan 15 2018 14:57:58 %S A298256 0,11,3,23,86,238,604,2492,7722,26880,93816,323639,1117834,3898368, %T A298256 13506089,46957460,163354721,567902351,1974550100,6868633724, %U A298256 23885771820,83075178134,288949706185,1004983567658,3495450659632,12157805469082 %N A298256 Number of nX5 0..1 arrays with every element equal to 2, 3, 5 or 8 king-move adjacent elements, with upper left element zero. %C A298256 Column 5 of A298259. %H A298256 R. H. Hardin, <a href="/A298256/b298256.txt">Table of n, a(n) for n = 1..210</a> %e A298256 Some solutions for n=7 %e A298256 ..0..0..1..1..1. .0..0..1..1..0. .0..0..0..1..1. .0..0..1..1..1 %e A298256 ..0..1..0..0..1. .0..1..1..0..0. .1..0..1..0..1. .0..1..0..0..1 %e A298256 ..0..1..1..1..0. .0..1..0..1..1. .1..1..1..0..1. .0..1..1..0..1 %e A298256 ..0..0..0..0..0. .0..1..0..0..1. .1..0..0..0..1. .1..0..0..1..1 %e A298256 ..1..1..1..1..1. .0..0..1..1..0. .0..1..1..1..0. .0..1..1..0..1 %e A298256 ..1..1..1..1..1. .1..0..0..1..0. .1..0..0..1..0. .0..0..1..0..0 %e A298256 ..1..1..1..1..1. .1..1..1..0..0. .1..1..1..0..0. .0..1..1..1..0 %Y A298256 Cf. A298259. %K A298256 nonn %O A298256 1,2 %A A298256 _R. H. Hardin_, Jan 15 2018