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 A208102 #9 Jul 22 2025 21:09:38 %S A208102 2,16,78,361,6235,261121,4747545,90782784,18473477832,9693564675601, %T A208102 668167531935849,46925086118316121,128627682135940435023, %U A208102 919037094400530117376144,213624920267877921384329046 %N A208102 Number of n X n 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 1 and 1 1 0 vertically. %C A208102 Diagonal of A208108 %H A208102 R. H. Hardin, <a href="/A208102/b208102.txt">Table of n, a(n) for n = 1..23</a> %e A208102 Some solutions for n=5 %e A208102 ..0..1..1..0..0....1..0..0..1..1....1..0..1..1..1....1..1..1..1..1 %e A208102 ..0..1..1..0..1....0..1..1..0..0....0..0..1..1..1....0..0..1..1..1 %e A208102 ..0..1..1..1..0....1..0..0..1..1....1..0..1..1..1....1..0..1..1..1 %e A208102 ..1..1..1..0..1....0..1..1..0..0....0..0..1..1..1....0..1..1..1..1 %e A208102 ..0..1..1..1..0....1..0..0..1..1....0..0..1..1..1....0..0..1..1..1 %K A208102 nonn %O A208102 1,1 %A A208102 _R. H. Hardin_ Feb 23 2012