|
%I #8 Sep 23 2019 06:26:54
%S 1,2,44,1904,168096,30818432,11838995200,9578237457408,
%T 16372889877477376,59262411624914853888,454901302416508366209024,
%U 7413673375795915677473636352
%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 horizontal, vertical or antidiagonal neighbor (colorings ignoring permutations of colors)
%C Diagonal of A208050
%e Some solutions for n=4
%e ..0..1..2..1....0..1..2..1....0..1..2..3....0..1..0..1....0..1..2..1
%e ..2..0..3..2....2..3..0..3....3..0..1..0....2..3..2..3....2..3..0..2
%e ..3..2..1..0....0..1..2..0....1..2..3..1....0..1..0..1....0..2..1..3
%e ..0..3..2..1....2..3..1..3....3..1..0..2....2..3..2..0....1..0..2..1
%t A208050 = Cases[Import["https://oeis.org/A208050/b208050.txt", "Table"], {_, _}][[All, 2]];
%t a[n_] := A208050[[2 n^2 - 2 n + 1]];
%t Table[a[n], {n, 1, 12}] (* _Jean-François Alcover_, Sep 23 2019 *)
%K nonn
%O 1,2
%A _R. H. Hardin_ Feb 22 2012
| 