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 A208043 #7 Jul 22 2025 21:08:30 %S A208043 28,784,5404,37249,422477,4791721,44918280,421070400,4242161160, %T A208043 42738533289,418847880189,4104809717089,40659110991088, %U A208043 402738109808896,3972693497773776,39187484975640681,387184769071171113 %N A208043 Number of 7Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 0 and 1 0 1 vertically. %C A208043 Row 7 of A208039 %H A208043 R. H. Hardin, <a href="/A208043/b208043.txt">Table of n, a(n) for n = 1..210</a> %e A208043 Some solutions for n=4 %e A208043 ..0..0..1..1....0..0..1..1....0..0..1..1....1..0..0..1....1..0..0..1 %e A208043 ..1..1..0..0....0..1..1..0....1..1..1..1....0..1..1..1....0..1..1..0 %e A208043 ..1..1..0..0....1..1..0..0....0..1..1..1....0..0..1..1....0..1..1..0 %e A208043 ..1..0..1..1....1..0..0..1....0..0..1..1....1..0..0..1....1..1..0..1 %e A208043 ..1..0..0..1....0..0..1..1....1..0..0..1....1..1..0..0....1..0..0..1 %e A208043 ..1..1..0..0....0..1..1..1....1..1..0..1....1..1..1..0....0..0..1..1 %e A208043 ..1..1..1..0....1..0..0..1....0..1..1..0....1..0..0..1....0..1..1..1 %K A208043 nonn %O A208043 1,1 %A A208043 _R. H. Hardin_ Feb 22 2012