A198709 Number of n X n 0..3 arrays with values 0..3 introduced in row major order and no element equal to any horizontal or vertical neighbor.

1, 4, 401, 250031, 851787199, 15835552812749, 1606578861528554441, 889483369334451647489771, 2687450673445984030296455830409

Offset: 1

Author

R. H. Hardin Oct 29 2011

Keywords

• nonn

Comments

Diagonal of A198715

Examples

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

Links

• Jean-François Alcover, Table of n, a(n) for n = 1..16

Programs

Mathematica

A198715 = Import["https://oeis.org/A198715/b198715.txt", "Table"][[All, 2]];
a[n_] := A198715[[2 n^2 - 2 n + 1]];
Table[a[n], {n, 1, 16}] (* Jean-François Alcover, Sep 23 2019 *)