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 A202798 #7 Jul 22 2025 16:50:39 %S A202798 7,126,1718,22946,311144,4217066,57127796,773948962,10485233258, %T A202798 142050385280,1924452482144,26071860295098,353213105139604, %U A202798 4785216541174944,64828561353680056,878276318748587482 %N A202798 Number of nX4 binary arrays with every one adjacent to another one horizontally or vertically. %C A202798 Column 4 of A202802 %H A202798 R. H. Hardin, <a href="/A202798/b202798.txt">Table of n, a(n) for n = 1..210</a> %F A202798 Empirical: a(n) = 13*a(n-1) -7*a(n-2) +181*a(n-3) +123*a(n-4) +940*a(n-5) +545*a(n-6) -2084*a(n-7) -1964*a(n-8) +1512*a(n-9) +1984*a(n-10) -512*a(n-11) -1024*a(n-12) %e A202798 Some solutions for n=4 %e A202798 ..0..0..1..1....1..1..0..0....1..1..1..0....0..1..1..0....0..0..0..0 %e A202798 ..1..0..0..1....0..0..0..0....0..0..1..1....0..0..1..0....1..0..1..1 %e A202798 ..1..1..1..0....0..0..1..1....1..1..1..0....0..0..0..0....1..1..0..0 %e A202798 ..0..1..0..0....0..0..1..0....1..0..1..0....0..0..1..1....0..1..1..0 %K A202798 nonn %O A202798 1,1 %A A202798 _R. H. Hardin_ Dec 24 2011