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 A297757 #4 Jan 05 2018 18:56:38 %S A297757 1,12,52,186,1045,5685,28565,148681,783104,4082179,21289432,111293510, %T A297757 581390557,3036127779,15859365566,82842802213,432710054944, %U A297757 2260195540670,11805906967573,61666590418664,322107101630217,1682485627292574 %N A297757 Number of nX3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2, 3 or 4 neighboring 1s. %C A297757 Column 3 of A297762. %H A297757 R. H. Hardin, <a href="/A297757/b297757.txt">Table of n, a(n) for n = 1..210</a> %F A297757 Empirical: a(n) = 3*a(n-1) +2*a(n-2) +52*a(n-3) +2*a(n-4) +27*a(n-5) -378*a(n-6) -365*a(n-7) -173*a(n-8) +386*a(n-9) +1006*a(n-10) +488*a(n-11) +468*a(n-12) +328*a(n-13) -120*a(n-14) -80*a(n-15) %e A297757 Some solutions for n=7 %e A297757 ..1..1..0. .0..1..1. .0..1..1. .1..1..0. .0..1..0. .0..1..1. .1..1..1 %e A297757 ..1..1..1. .1..1..0. .1..1..0. .1..1..0. .1..1..1. .0..1..1. .0..1..0 %e A297757 ..0..1..0. .1..1..0. .0..1..1. .0..1..1. .0..1..0. .0..1..1. .0..1..0 %e A297757 ..0..0..0. .0..1..0. .0..1..1. .0..0..0. .1..1..1. .0..0..0. .1..0..1 %e A297757 ..0..1..0. .1..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .1..1..0 %e A297757 ..1..1..1. .1..1..1. .0..1..1. .1..1..1. .1..1..1. .1..1..1. .0..1..1 %e A297757 ..0..1..0. .0..0..0. .1..1..1. .0..0..0. .1..1..1. .1..1..0. .1..1..0 %Y A297757 Cf. A297762. %K A297757 nonn %O A297757 1,2 %A A297757 _R. H. Hardin_, Jan 05 2018