A239532 Number of (n+1) X (3+1) 0..2 arrays with no element equal to all horizontal neighbors or unequal to all vertical neighbors, and new values 0..2 introduced in row major order.

6, 6, 216, 1014, 13254, 98304, 984150, 8368566, 77673624, 687582150, 6243858486, 55924463616, 504631320486, 4535315519334, 40848737643864, 367488643786134, 3308125850845350, 29769598506080256, 267943541451802614

Offset: 1

Author

R. H. Hardin, Mar 21 2014

Keywords

• nonn

Examples

			Some solutions for n=5:
..0..1..0..2....0..1..0..1....0..1..1..0....0..1..2..0....0..1..2..1
..0..1..0..2....0..1..0..1....0..1..1..0....0..1..2..0....0..1..2..1
..1..0..0..2....0..1..2..1....0..1..2..1....1..0..1..2....2..1..0..1
..1..0..0..2....0..2..2..1....1..2..2..1....1..0..1..2....2..0..0..1
..0..1..1..0....0..2..0..1....1..2..2..1....1..0..2..0....1..0..2..1
..0..1..1..0....0..2..0..1....1..2..2..1....1..0..2..0....1..0..2..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Column 3 of A239537.

Formula

Empirical: a(n) = 8*a(n-1) + 26*a(n-2) - 166*a(n-3) + 96*a(n-4) + 198*a(n-5) - 81*a(n-6).

Empirical g.f.: 6*(1 - 7*x + 2*x^2 + 21*x^3 - 9*x^4) / ((1 + x)*(1 - 9*x)*(1 - 3*x + x^2)*(1 + 3*x - 9*x^2)). - Colin Barker, Oct 26 2018