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 A297649 #4 Jan 02 2018 15:05:44 %S A297649 4,43,231,1421,9033,55706,346032,2151932,13364992,83036263,515911384, %T A297649 3205231551,19913717003,123721335945,768662962676,4775598530205, %U A297649 29670139081754,184336490377417,1145257318539730,7115326466070793 %N A297649 Number of nX3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1, 2 or 3 neighboring 1s. %C A297649 Column 3 of A297654. %H A297649 R. H. Hardin, <a href="/A297649/b297649.txt">Table of n, a(n) for n = 1..210</a> %F A297649 Empirical: a(n) = 3*a(n-1) +9*a(n-2) +60*a(n-3) +51*a(n-4) +54*a(n-5) -303*a(n-6) -336*a(n-7) -234*a(n-8) +316*a(n-9) +264*a(n-10) -144*a(n-11) %e A297649 Some solutions for n=6 %e A297649 ..1..1..1. .0..0..0. .0..1..1. .0..0..1. .1..1..0. .0..0..0. .0..1..0 %e A297649 ..1..1..0. .0..1..1. .1..0..1. .1..1..0. .0..0..1. .0..1..0. .0..0..1 %e A297649 ..0..0..0. .0..0..0. .1..1..0. .0..0..0. .1..1..1. .0..1..1. .1..0..1 %e A297649 ..0..0..0. .0..0..0. .0..1..0. .1..1..1. .0..0..0. .0..1..1. .0..1..0 %e A297649 ..1..1..1. .1..1..0. .0..0..1. .0..1..1. .1..1..0. .0..1..0. .0..1..1 %e A297649 ..0..1..0. .1..0..1. .0..1..1. .0..1..0. .1..0..0. .1..0..1. .0..0..0 %Y A297649 Cf. A297654. %K A297649 nonn %O A297649 1,1 %A A297649 _R. H. Hardin_, Jan 02 2018