A223581 - OEIS

%I #6 Mar 22 2013 18:13:30

%S 256,65536,10240000,1331200000,173056000000,22497280000000,

%T 2924646400000000,380204032000000000,49426524160000000000,

%U 6425448140800000000000,835308258304000000000000

%N Number of nX4 0..3 arrays with antidiagonals unimodal

%C Column 4 of A223585

%H R. H. Hardin, <a href="/A223581/b223581.txt">Table of n, a(n) for n = 1..210</a>

%F Let U(z) = (z^6+15*z^5+115*z^4+405*z^3+964*z^2+660*z+720)/720

%F a(n) = U(min(n,4))^(max(n,4)-min(n,4)+1) * product{ U(i)^2 , i=1..(min(n,4)-1) }

%F a(n) = 130*a(n-1) for n>3

%e Some solutions for n=3

%e ..0..0..2..1....0..0..3..0....0..2..2..1....0..0..2..0....0..0..0..2

%e ..0..1..3..1....0..3..2..1....0..0..1..2....0..2..1..1....0..3..3..3

%e ..1..2..3..3....1..1..3..1....0..1..1..1....0..3..0..1....1..2..0..3

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 22 2013