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 A223570 #10 Jul 23 2025 04:14:20
%S A223570 3,81,16038,16230456,64207683936,817235401137408,28907250609032395776,
%T A223570 2535541672670058530700288,503424192483622111094950081536,
%U A223570 209983768351036102380925723459562496
%N A223570 Number of n X n 0..2 arrays with antidiagonals unimodal.
%C A223570 Diagonal of A223576
%H A223570 R. H. Hardin, <a href="/A223570/b223570.txt">Table of n, a(n) for n = 1..64</a>
%F A223570 Let U(z) = (z^4+6*z^3+23*z^2+18*z+24)/24
%F A223570 a(n) = U(n) * product{ U(i)^2 , i=1..(n-1) }
%e A223570 Some solutions for n=3
%e A223570 ..1..0..2....0..2..1....2..1..2....1..0..2....0..0..0....1..2..0....0..0..0
%e A223570 ..1..1..2....1..1..1....2..2..0....1..0..1....0..1..0....0..1..0....1..0..2
%e A223570 ..1..1..0....0..0..0....2..1..1....0..1..2....1..1..1....2..0..0....0..0..0
%K A223570 nonn
%O A223570 1,1
%A A223570 _R. H. Hardin_ Mar 22 2013