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 A224405 #8 Aug 30 2018 06:07:41 %S A224405 11,56,228,884,3436,13440,52700,206708,810664,3178940,12465596, %T A224405 48881440,191679756,751638532,2947419144,11557788332,45321842028, %U A224405 177721660896,696904347580,2732788270804,10716150306024,42021505514844 %N A224405 Number of n X 4 0..1 arrays with rows unimodal and antidiagonals nondecreasing. %C A224405 Column 4 of A224409. %H A224405 R. H. Hardin, <a href="/A224405/b224405.txt">Table of n, a(n) for n = 1..210</a> %F A224405 Empirical: a(n) = 5*a(n-1) - 5*a(n-2) + 2*a(n-3) + 4*a(n-4). %F A224405 Empirical g.f.: x*(11 + x + 3*x^2 + 2*x^3) / (1 - 5*x + 5*x^2 - 2*x^3 - 4*x^4). - _Colin Barker_, Aug 30 2018 %e A224405 Some solutions for n=3: %e A224405 ..0..0..0..0....1..1..0..0....0..0..1..1....0..1..1..1....0..1..0..0 %e A224405 ..1..1..0..0....1..1..0..0....1..1..1..1....1..1..1..0....1..0..0..0 %e A224405 ..1..0..0..0....1..1..0..0....1..1..1..1....1..1..1..0....0..1..0..0 %Y A224405 Cf. A224409. %K A224405 nonn %O A224405 1,1 %A A224405 _R. H. Hardin_, Apr 05 2013