A208346 - OEIS

%I #6 Dec 18 2015 18:18:03

%S 1,15,1095,230387,191586797,647640659639

%N Number of n X n 0..3 arrays with new values 0..3 introduced in row major order and no element equal to any knight-move neighbor (colorings ignoring permutations of colors)

%C Diagonal of A208353

%e Some solutions for n=4

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

%e ..0..1..2..0....2..1..1..2....0..2..2..1....0..0..1..2....1..1..1..1

%e ..0..2..2..2....2..3..1..0....3..3..3..0....3..3..3..3....2..2..2..3

%e ..3..1..2..0....2..3..3..2....1..3..0..0....1..2..1..2....0..2..3..0

%K nonn

%O 1,2

%A _R. H. Hardin_ Feb 25 2012