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 A208113 #9 Jul 22 2025 21:10:24 %S A208113 2,16,90,625,7315,130321,1432600,17850625,339961440,8208541201, %T A208113 137250396283,2528484794641,64191779662920,1915940360359936, %U A208113 43397063924977512,1065586805357114881,33367357471586657167 %N A208113 Number of n X n 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 0 1 1 vertically. %C A208113 Diagonal of A208118 %H A208113 R. H. Hardin, <a href="/A208113/b208113.txt">Table of n, a(n) for n = 1..38</a> %e A208113 Some solutions for n=4 %e A208113 ..1..1..0..0....0..1..1..1....0..1..1..1....1..1..0..1....0..1..1..0 %e A208113 ..1..1..1..0....0..1..1..1....1..0..0..1....1..0..1..1....1..0..1..1 %e A208113 ..1..1..0..0....0..1..1..1....0..1..1..1....1..0..0..1....0..1..1..0 %e A208113 ..1..1..0..0....0..1..1..1....1..0..0..1....0..0..1..1....1..0..1..1 %K A208113 nonn %O A208113 1,1 %A A208113 _R. H. Hardin_ Feb 23 2012