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 A206930 #8 Dec 30 2023 21:53:37 %S A206930 2,16,211,6837,418876,40316253,8138711727,2968348851593, %T A206930 1635655868695143,1996781212118762256,4440970754945359464401, %U A206930 13563038968625915203795793 %N A206930 Number of n X n 0..1 arrays avoiding 0 0 0 horizontally and 0 1 1 vertically. %C A206930 Diagonal of A206936. %e A206930 Some solutions for n=4 %e A206930 ..1..1..0..1....1..1..1..0....1..1..0..1....1..1..0..1....0..1..1..0 %e A206930 ..1..0..0..1....0..0..1..1....0..1..0..1....1..1..0..1....0..0..1..0 %e A206930 ..0..0..1..0....1..1..1..0....1..0..0..1....0..1..1..0....0..0..1..1 %e A206930 ..0..1..0..1....0..0..1..0....0..1..0..1....0..1..0..0....0..0..1..0 %Y A206930 Cf. A206936. %K A206930 nonn %O A206930 1,1 %A A206930 _R. H. Hardin_, Feb 13 2012