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 A262268 #7 Dec 31 2018 05:46:00 %S A262268 4,16,49,169,676,2704,10609,42025,168100,672400,2686321,10738729, %T A262268 42954916,171819664,687226225,2748800041,10995200164,43980800656, %U A262268 175922363761,703687777321,2814751109284,11259004437136,45036004326769 %N A262268 Number of (n+2) X (2+2) 0..1 arrays with each row and column divisible by 5, read as a binary number with top and left being the most significant bits. %H A262268 R. H. Hardin, <a href="/A262268/b262268.txt">Table of n, a(n) for n = 1..210</a> %F A262268 Empirical: a(n) = 6*a(n-1) - 12*a(n-2) + 24*a(n-3) - 31*a(n-4) - 6*a(n-5) + 12*a(n-6) - 24*a(n-7) + 32*a(n-8). %F A262268 Empirical g.f.: x*(4 - 8*x + x^2 - 29*x^3 - 10*x^4 + 20*x^5 + 8*x^6 + 32*x^7) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - 4*x)*(1 + x^2)*(1 + 4*x^2)). - _Colin Barker_, Dec 31 2018 %e A262268 Some solutions for n=4: %e A262268 ..1..1..1..1....0..0..0..0....0..0..0..0....0..0..0..0....0..1..0..1 %e A262268 ..1..0..1..0....1..1..1..1....1..0..1..0....1..1..1..1....1..0..1..0 %e A262268 ..0..1..0..1....0..1..0..1....1..1..1..1....0..0..0..0....1..1..1..1 %e A262268 ..0..1..0..1....1..1..1..1....0..0..0..0....1..1..1..1....0..1..0..1 %e A262268 ..1..0..1..0....0..1..0..1....0..1..0..1....0..0..0..0....0..0..0..0 %e A262268 ..0..1..0..1....0..0..0..0....1..0..1..0....0..0..0..0....1..1..1..1 %Y A262268 Column 2 of A262274. %K A262268 nonn %O A262268 1,1 %A A262268 _R. H. Hardin_, Sep 17 2015