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 A297304 #4 Dec 27 2017 21:18:53 %S A297304 1,1,21,69,266,1574,13504,93906,551477,3159693,18792129,113862870, %T A297304 692747205,4226551294,25828653795,157805371000,963306137176, %U A297304 5876339680839,35834865220658,218515617055715,1332575380148292 %N A297304 Number of 7Xn 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 2 neighboring 1s. %C A297304 Row 7 of A297299. %H A297304 R. H. Hardin, <a href="/A297304/b297304.txt">Table of n, a(n) for n = 1..210</a> %e A297304 Some solutions for n=5 %e A297304 ..0..1..1..0..0. .0..0..1..1..0. .0..0..0..1..1. .0..0..0..0..0 %e A297304 ..1..1..0..0..0. .0..1..1..0..0. .0..0..1..1..0. .0..1..1..0..0 %e A297304 ..0..0..0..0..0. .0..0..1..1..1. .0..0..0..0..0. .1..1..0..0..0 %e A297304 ..0..0..0..0..0. .0..1..0..1..1. .0..1..1..0..0. .0..1..1..0..0 %e A297304 ..0..0..0..0..0. .1..1..0..1..0. .1..1..0..1..1. .1..1..0..0..0 %e A297304 ..0..0..0..1..1. .1..1..1..0..0. .0..0..1..1..0. .0..1..1..0..0 %e A297304 ..0..0..1..1..0. .0..0..0..0..0. .0..0..0..0..0. .1..1..0..0..0 %Y A297304 Cf. A297299. %K A297304 nonn %O A297304 1,3 %A A297304 _R. H. Hardin_, Dec 27 2017