A223570 - OEIS

%I #8 Dec 18 2015 18:18:31

%S 3,81,16038,16230456,64207683936,817235401137408,28907250609032395776,

%T 2535541672670058530700288,503424192483622111094950081536,

%U 209983768351036102380925723459562496

%N Number of n X n 0..2 arrays with antidiagonals unimodal

%C Diagonal of A223576

%H R. H. Hardin, <a href="/A223570/b223570.txt">Table of n, a(n) for n = 1..64</a>

%F Let U(z) = (z^4+6*z^3+23*z^2+18*z+24)/24

%F a(n) = U(n) * product{ U(i)^2 , i=1..(n-1) }

%e Some solutions for n=3

%e ..1..0..2....0..2..1....2..1..2....1..0..2....0..0..0....1..2..0....0..0..0

%e ..1..1..2....1..1..1....2..2..0....1..0..1....0..1..0....0..1..0....1..0..2

%e ..1..1..0....0..0..0....2..1..1....0..1..2....1..1..1....2..0..0....0..0..0

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 22 2013