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 A302311 #6 Sep 03 2022 21:42:28 %S A302311 4,6,13,26,48,121,275,600,1296,2998,6731,15022,33412,75480,169232, %T A302311 379265,848913,1907065,4276079,9589159,21494910,48224727,108142434, %U A302311 242526545,543834226,1219737296,2735350513,6134430103,13756843652,30852213480 %N A302311 Number of 3 X n 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302311 Row 3 of A302309. %H A302311 R. H. Hardin, <a href="/A302311/b302311.txt">Table of n, a(n) for n = 1..210</a> %F A302311 Empirical: a(n) = a(n-1) +3*a(n-2) -a(n-3) +8*a(n-4) -7*a(n-5) -22*a(n-6) +9*a(n-7) -14*a(n-8) +10*a(n-9) +39*a(n-10) -19*a(n-11) +6*a(n-12) -18*a(n-14) +9*a(n-15) for n>16. %e A302311 Some solutions for n=5 %e A302311 ..0..1..0..1..0. .0..0..1..0..1. .0..0..1..0..1. .0..1..1..1..0 %e A302311 ..0..1..0..1..1. .0..1..0..0..1. .1..1..1..0..0. .0..1..0..1..0 %e A302311 ..0..1..0..1..0. .0..1..0..1..0. .0..0..1..0..1. .0..1..0..0..0 %Y A302311 Cf. A302309. %K A302311 nonn %O A302311 1,1 %A A302311 _R. H. Hardin_, Apr 05 2018