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 A207413 #10 Jul 22 2025 20:23:14 %S A207413 2,16,92,742,13260,220882,4094666,129528304,4643477356,183171965504, %T A207413 10948746139548,797831881523648,65446536338563458,7746605907720894574, %U A207413 1149785247198798823392,195841032765969991278104 %N A207413 Number of n X n 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 1 1 and 1 0 1 vertically. %C A207413 Diagonal of A207419 %H A207413 R. H. Hardin, <a href="/A207413/b207413.txt">Table of n, a(n) for n = 1..17</a> %e A207413 Some solutions for n=4 %e A207413 ..1..0..0..0....0..0..0..0....0..1..1..1....1..1..0..0....1..1..0..1 %e A207413 ..1..1..1..1....1..1..0..1....1..1..1..0....1..1..1..0....1..1..0..1 %e A207413 ..1..0..0..0....0..0..0..0....0..0..0..0....1..0..0..0....0..1..1..0 %e A207413 ..1..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0 %K A207413 nonn %O A207413 1,1 %A A207413 _R. H. Hardin_ Feb 17 2012