A221291 - OEIS

%I #3 Jan 09 2013 12:43:25

%S 1,12,92,673,5912,48298,396846,3240527,26241353,211785583,1703772887,

%T 13679840407,109689414233,878752161168,7035829547262,56311795445487

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

%C Row 3 of A221290

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 09 2013