login
Number of nX4 binary arrays with rows and columns in nondecreasing order
1

%I #5 Mar 31 2012 12:35:56

%S 5,25,130,650,2942,11819,42305,136564,402910,1099694,2805530,6748066,

%T 15412437,33626131,70430778,142218719,277853339,526833235,972034814,

%U 1749218190,3076360192,5297051455,8943742419,14828643610,24172697276

%N Number of nX4 binary arrays with rows and columns in nondecreasing order

%C Column 4 of A180985

%H R. H. Hardin, <a href="/A184139/b184139.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n)=16*a(n-1)-120*a(n-2)+560*a(n-3)-1820*a(n-4)+4368*a(n-5)-8008*a(n-6)+11440*a(n-7)-12870*a(n-8)+11440*a(n-9)-8008*a(n-10)+4368*a(n-11)-1820*a(n-12)+560*a(n-13)-120*a(n-14)+16*a(n-15)-a(n-16) (=polynomial degree 15)

%e Some solutions for 3X4

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 09 2011