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 A228665 #12 Sep 02 2025 21:57:46 %S A228665 32,70,2348,11912,203762,1482892,19236832,166237206,1899605260, %T A228665 17848767224,192044287042,1879682471996,19647967583440, %U A228665 196172283670342,2022115572124828,20385597248657864,208716533500704978,2114033802192686572,21573650422984183744,219011665920930992374 %N A228665 Number of 6 X n binary arrays with top left value 1 and no two ones adjacent horizontally, diagonally or antidiagonally. %H A228665 R. H. Hardin, <a href="/A228665/b228665.txt">Table of n, a(n) for n = 1..210</a> %F A228665 Empirical: a(n) = 4*a(n-1) +88*a(n-2) -138*a(n-3) -1388*a(n-4) +1332*a(n-5) +5911*a(n-6) -2920*a(n-7) -8340*a(n-8) +816*a(n-9) +2232*a(n-10). %e A228665 Some solutions for n=4: %e A228665 ..1..0..0..1....1..0..0..0....1..0..0..0....1..0..1..0....1..0..1..0 %e A228665 ..0..0..0..1....0..0..1..0....0..0..0..0....1..0..1..0....0..0..0..0 %e A228665 ..0..1..0..0....1..0..0..0....0..0..1..0....1..0..1..0....1..0..1..0 %e A228665 ..0..0..0..0....0..0..0..1....1..0..1..0....1..0..0..0....0..0..0..0 %e A228665 ..0..0..0..1....0..1..0..1....0..0..1..0....0..0..0..0....1..0..1..0 %e A228665 ..0..1..0..1....0..1..0..0....1..0..0..0....0..0..0..0....0..0..0..0 %Y A228665 Row 6 of A228660. %K A228665 nonn,changed %O A228665 1,1 %A A228665 _R. H. Hardin_, Aug 29 2013