A198716 Number of n X n 0..6 arrays with values 0..6 introduced in row major order and no element equal to any horizontal or vertical neighbor.

1, 4, 2027, 173549032, 601755060211186, 56817439251356046537693, 143258513960209594417739070314380, 9642423210031999968965088302478619142184723, 17325184073281687394967689689039757737268207918711712613, 830989324900948864881160725155158690837481885610384662473963254527609

Offset: 1

Author

R. H. Hardin, Oct 29 2011

Keywords

• nonn

Examples

			Some solutions with all values 0 to 6 for n=4
..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
..2..3..1..0....2..3..1..0....2..3..1..0....2..3..1..0....2..3..1..0
..4..5..2..4....4..0..5..2....0..1..4..3....4..1..0..5....4..2..0..5
..6..0..6..1....6..4..6..0....1..5..3..6....1..6..2..1....3..1..6..1
		

Links

• Jean-François Alcover, Table of n, a(n) for n = 1..13

Crossrefs

Diagonal of A198723.

Programs

Mathematica

A198723 = Cases[Import["https://oeis.org/A198723/b198723.txt", "Table"], {, }][[All, 2]];
a[n_] := A198723[[2 n^2 - 2 n + 1]];
Table[a[n], {n, 1, 13}] (* Jean-François Alcover, Sep 23 2019 *)

Extensions

More terms from Jean-François Alcover, Sep 23 2019