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 A297512 #4 Dec 31 2017 07:33:36 %S A297512 1,2735,53175,573119,35919085,1272836591,28914051279,949224569894, %T A297512 32507021089982,940396282368163,28523594741249476,910897573503281049, %U A297512 27940827448011878850,852581385081080135117,26505475722899552411184 %N A297512 Number of 7Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 2 neighboring 1s. %C A297512 Row 7 of A297506. %H A297512 R. H. Hardin, <a href="/A297512/b297512.txt">Table of n, a(n) for n = 1..210</a> %e A297512 Some solutions for n=3 %e A297512 ..0..1..0. .0..0..0. .0..0..1. .0..1..1. .0..1..1. .0..1..1. .0..0..1 %e A297512 ..1..0..0. .1..1..1. .0..1..0. .1..0..0. .1..0..0. .0..0..1. .0..1..0 %e A297512 ..0..0..0. .0..0..0. .0..0..1. .0..0..0. .0..1..1. .0..0..0. .0..0..1 %e A297512 ..1..0..0. .0..0..0. .0..1..1. .0..1..1. .0..1..0. .0..1..1. .0..1..0 %e A297512 ..1..1..0. .0..0..0. .0..1..0. .0..0..0. .0..0..1. .1..0..0. .0..0..1 %e A297512 ..0..0..0. .0..0..1. .1..1..0. .1..1..1. .1..0..1. .1..1..0. .1..0..0 %e A297512 ..0..1..1. .1..1..0. .1..0..0. .0..1..0. .0..1..0. .0..0..0. .0..1..0 %Y A297512 Cf. A297506. %K A297512 nonn %O A297512 1,2 %A A297512 _R. H. Hardin_, Dec 31 2017