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 A297724 #4 Jan 04 2018 22:02:08 %S A297724 1,280,4090,34319,512354,8103241,107787351,1446088760,20410564866, %T A297724 284834549399,3925719705949,54393595038381,755754672219017, %U A297724 10479694450894966,145249271559341180,2014480587809008069 %N A297724 Number of 5Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1, 2 or 4 neighboring 1s. %C A297724 Row 5 of A297720. %H A297724 R. H. Hardin, <a href="/A297724/b297724.txt">Table of n, a(n) for n = 1..210</a> %e A297724 Some solutions for n=4 %e A297724 ..0..1..1..0. .0..0..1..1. .1..1..0..0. .0..0..1..1. .0..0..0..0 %e A297724 ..0..0..0..1. .0..0..0..0. .1..0..0..0. .0..0..0..1. .0..0..0..1 %e A297724 ..0..0..0..0. .1..1..1..1. .1..0..1..1. .0..1..0..0. .1..1..1..1 %e A297724 ..0..0..0..0. .0..1..0..1. .0..1..0..0. .0..1..1..1. .0..1..0..0 %e A297724 ..0..0..1..1. .1..1..1..1. .1..1..1..0. .1..0..0..1. .1..0..1..1 %Y A297724 Cf. A297720. %K A297724 nonn %O A297724 1,2 %A A297724 _R. H. Hardin_, Jan 04 2018