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 A223572 #8 Jul 23 2025 04:14:32
%S A223572 81,6561,352836,16230456,746600976,34343644896,1579807665216,
%T A223572 72671152599936,3342873019597056,153772158901464576,
%U A223572 7073519309467370496,325381888235499042816,14967566858832955969536,688508075506315974598656
%N A223572 Number of nX4 0..2 arrays with antidiagonals unimodal.
%C A223572 Column 4 of A223576
%H A223572 R. H. Hardin, <a href="/A223572/b223572.txt">Table of n, a(n) for n = 1..210</a>
%F A223572 Let U(z) = (z^4+6*z^3+23*z^2+18*z+24)/24
%F A223572 a(n) = U(min(n,4))^(max(n,4)-min(n,4)+1) * product{ U(i)^2 , i=1..(min(n,4)-1) }
%F A223572 a(n) = 46*a(n-1) for n>3
%e A223572 Some solutions for n=3
%e A223572 ..0..2..2..2....0..2..2..0....0..2..0..1....0..1..1..0....0..1..1..0
%e A223572 ..1..0..2..2....1..1..0..1....1..0..2..0....2..0..0..1....1..1..2..0
%e A223572 ..0..2..0..0....0..1..2..2....2..0..1..1....0..0..2..2....2..2..2..1
%K A223572 nonn
%O A223572 1,1
%A A223572 _R. H. Hardin_ Mar 22 2013