A183290 - OEIS

%I #6 Mar 31 2012 12:35:50

%S 1,3,75,43857,960006269,1466084347024748,302925464053912372874616,

%T 16658979732689967888192414390784353,

%U 482781472857798712221209645418994183476323697006

%N Half the number of nXnXnXn triangular pyramidal binary arrays with the number of 0-0 adjacencies equal to the number of 1-1 adjacencies

%H R. H. Hardin, <a href="/A183290/b183290.txt">Table of n, a(n) for n = 1..18</a>

%e Some solutions for 3X3X3X3 with a(1,1,1)=0

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

%e ...

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

%e ...0.0....0.0....0.0....0.1....0.1....0.1....0.1....0.1....0.1....0.1....0.1

%e ...

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

%e ...1.1....1.1....1.1....0.1....0.1....0.1....1.0....1.0....1.0....1.1....1.1

%e ..1.1.1..0.1.1..1.1.0..1.1.1..0.1.1..1.1.0..1.1.1..0.1.1..1.1.0..1.0.1..0.0.1

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 03 2011