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 A297308 #7 Apr 19 2020 23:55:56 %S A297308 1,7,117,3808,484808,200646607,197589351469,578079526400673, %T A297308 5377924483062338484,139752957415982420114129, %U A297308 10302206214700301342887034910,2267938084956284272782357464419480 %N A297308 Number of n X n 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 1 or 2 neighboring 1's. %C A297308 Diagonal of A297314. %H A297308 R. H. Hardin, <a href="/A297308/b297308.txt">Table of n, a(n) for n = 1..17</a> %e A297308 Some solutions for n=5 %e A297308 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..1..0..1..1 %e A297308 ..0..1..1..0..0. .1..1..0..0..0. .0..0..0..0..0. .1..1..0..1..1 %e A297308 ..0..0..0..1..0. .0..1..0..0..0. .1..1..0..0..0. .1..1..0..0..0 %e A297308 ..0..0..1..0..0. .1..0..0..1..1. .0..1..1..0..0. .1..1..0..0..0 %e A297308 ..0..0..0..1..1. .0..0..0..0..0. .0..1..1..0..0. .1..0..0..1..1 %Y A297308 Cf. A297314. %K A297308 nonn %O A297308 1,2 %A A297308 _R. H. Hardin_, Dec 28 2017