A221292 - OEIS

%I #3 Jan 09 2013 12:48:57

%S 1,37,556,9107,172904,2890017,49684593,821323042,13475380990

%N Equals two maps: number of 4Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..3 4Xn array

%C Row 4 of A221290

%e Some solutions for n=3

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

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 09 2013