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

Offset

1,2

Comments

Diagonal of A198723

Links

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

Example

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

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 *)

Crossrefs

Sequence in context: A198975 A160300 A024060 * A365369 A004815 A198907

Adjacent sequences: A198713 A198714 A198715 * A198717 A198718 A198719

Keyword

nonn

Author

R. H. Hardin Oct 29 2011

Status

approved