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 A208282 #9 Jul 22 2025 21:16:14 %S A208282 2,16,102,984,9900,119580,1604862,24229696,403795242,7388858420, %T A208282 147219127000,3175214941800,73720244775658,1833809960513104, %U A208282 48667824127404150,1372862920890984032,41025768742532649684 %N A208282 Number of n X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 1 0 vertically. %C A208282 Diagonal of A208287 %H A208282 R. H. Hardin, <a href="/A208282/b208282.txt">Table of n, a(n) for n = 1..25</a> %e A208282 Some solutions for n=4 %e A208282 ..1..1..1..1....1..1..0..0....1..0..1..0....0..1..1..0....1..1..1..0 %e A208282 ..0..1..0..1....1..0..1..0....1..1..0..1....0..1..1..0....0..1..1..0 %e A208282 ..1..1..1..1....1..1..0..0....1..1..1..1....0..1..1..0....1..1..1..0 %e A208282 ..0..1..0..1....1..1..1..0....1..1..1..1....0..1..1..0....1..1..1..0 %K A208282 nonn %O A208282 1,1 %A A208282 _R. H. Hardin_ Feb 25 2012