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 A224033 #8 Aug 26 2018 09:50:40 %S A224033 4,13,37,105,298,848,2419,6908,19737,56401,161181,460622,1316360, %T A224033 3761867,10750568,30722673,87798365,250907593,717036338,2049125344, %U A224033 5855930115,16734904820,47824518777,136671503209,390575802373,1116176041318 %N A224033 Number of n X 3 0..1 arrays with antidiagonals unimodal and rows and diagonals nondecreasing. %C A224033 Column 3 of A224038. %H A224033 R. H. Hardin, <a href="/A224033/b224033.txt">Table of n, a(n) for n = 1..210</a> %F A224033 Empirical: a(n) = 4*a(n-1) - 3*a(n-2) - a(n-3) + 2*a(n-5). %F A224033 Empirical g.f.: x*(1 - x)*(4 + x - 2*x^2 - 2*x^3) / (1 - 4*x + 3*x^2 + x^3 - 2*x^5). - _Colin Barker_, Aug 26 2018 %e A224033 Some solutions for n=3: %e A224033 ..0..0..1....0..0..0....0..0..0....0..0..0....0..0..0....0..1..1....0..0..0 %e A224033 ..0..1..1....1..1..1....0..0..1....0..0..0....0..0..0....1..1..1....0..1..1 %e A224033 ..1..1..1....0..1..1....1..1..1....0..0..1....0..1..1....1..1..1....0..1..1 %Y A224033 Cf. A224038. %K A224033 nonn %O A224033 1,1 %A A224033 _R. H. Hardin_, Mar 30 2013