A207993 Number of n X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors).

1, 3, 41, 1302, 96831, 16932816, 6978332618, 6787438272198, 15595829208171337, 84713253582265127190, 1088296274542436098185362, 33079232010276428576508643620, 2379573338713223879592059518246838

Offset: 1

Author

R. H. Hardin, Feb 22 2012

Keywords

• nonn

Comments

Diagonal of A207997.

Examples

			Some solutions for n=4
..0..1..0..1....0..1..2..0....0..1..2..0....0..1..2..0....0..1..2..1
..1..2..1..0....1..0..1..2....2..0..1..2....1..2..0..2....2..0..1..2
..2..0..2..1....2..1..2..0....1..2..0..1....2..0..1..0....1..2..0..1
..0..1..0..2....0..2..0..1....2..1..2..0....1..2..0..1....2..0..1..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..16

Programs

Mathematica

A207997 = Import["https://oeis.org/A207997/b207997.txt", "Table"][[All, 2]];
a[n_] := A207997[[2 n^2 - 2 n + 1]];
Table[a[n], {n, 1, 16}] (* Jean-François Alcover, Sep 23 2019 *)