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 A302267 #7 Apr 05 2018 04:10:29 %S A302267 4,32,153,772,3818,19191,96004,481261,2411557,12086268,60572976, %T A302267 303579352,1521476119,7625336613,38216661796,191534345225, %U A302267 959932146275,4810989844333,24111728148027,120843206657400,605642220203867 %N A302267 Number of 3 X n 0..1 arrays with every element equal to 0, 1, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302267 Row 3 of A302265. %H A302267 R. H. Hardin, <a href="/A302267/b302267.txt">Table of n, a(n) for n = 1..210</a> %F A302267 Empirical: a(n) = 3*a(n-1) +14*a(n-2) -9*a(n-3) -54*a(n-4) -10*a(n-5) +65*a(n-6) +17*a(n-7) -8*a(n-8) -2*a(n-9) -31*a(n-10) -7*a(n-11) +9*a(n-12) for n>13. %e A302267 Some solutions for n=5: %e A302267 0 1 0 0 1 0 1 0 0 1 0 1 0 1 0 0 0 1 0 0 %e A302267 1 0 0 1 0 0 1 0 0 1 1 0 0 0 1 0 1 1 0 1 %e A302267 1 1 1 0 1 1 0 0 1 1 1 0 1 1 1 0 1 1 0 1 %Y A302267 Cf. A302265. %K A302267 nonn %O A302267 1,1 %A A302267 _R. H. Hardin_, Apr 04 2018