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 A224403 #8 Jul 23 2025 05:09:35 %S A224403 2,12,100,884,7812,68282,590254,5055858,42996954,363652198,3062704166, %T A224403 25711681080,215327121414,1799987423914,15026012170736, %U A224403 125307656075926,1044220994847456,8697261784264396,72413790737672880,602789200212580366 %N A224403 Number of n X n 0..1 arrays with rows unimodal and antidiagonals nondecreasing. %C A224403 Diagonal of A224409 %H A224403 R. H. Hardin, <a href="/A224403/b224403.txt">Table of n, a(n) for n = 1..50</a> %e A224403 Some solutions for n=3 %e A224403 ..0..0..0....1..0..0....0..0..0....0..0..0....1..0..0....0..0..1....0..0..0 %e A224403 ..0..0..1....0..0..1....1..0..0....1..0..0....1..1..1....0..1..0....0..1..0 %e A224403 ..1..1..1....1..1..0....0..1..1....0..0..1....1..1..1....1..0..0....1..1..1 %K A224403 nonn %O A224403 1,1 %A A224403 _R. H. Hardin_ Apr 05 2013