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 A208694 #8 Jul 22 2025 21:28:02 %S A208694 2,16,98,1309,30160,1415508,126827983,22125222702,7392844742356, %T A208694 4723174261254577,5746602867110840996,13284653021118899451246, %U A208694 58277226038377671962460367,484690813727478247761183804458 %N A208694 Number of n X n 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 1 0 and 1 0 1 vertically. %C A208694 Diagonal of A208698 %e A208694 Some solutions for n=4 %e A208694 ..1..0..1..1....1..0..1..0....0..1..1..1....0..0..0..0....1..1..0..1 %e A208694 ..0..1..1..1....1..1..1..1....1..0..1..0....0..1..1..0....1..0..1..0 %e A208694 ..0..1..1..1....1..1..1..1....1..0..1..0....0..1..1..0....1..0..1..0 %e A208694 ..0..1..1..0....1..0..1..1....0..0..0..0....1..0..1..1....0..0..0..0 %K A208694 nonn %O A208694 1,1 %A A208694 _R. H. Hardin_ Mar 01 2012