A220329 - OEIS

%I #4 Dec 10 2012 18:14:27

%S 1,4,16,48,174,658,2482,9229,33982,125217,461351,1699127,6252129,

%T 22995280,84546207,310785413,1142206689,4197260747,15421867303,

%U 56659522539,208152496049,764662949438,2808941077111,10318186228202

%N Equals two maps: number of 2Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..1 2Xn array

%C Row 2 of A220328

%H R. H. Hardin, <a href="/A220329/b220329.txt">Table of n, a(n) for n = 1..210</a>

%e Some solutions for n=3

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 10 2012