A276300 Number of 3 X n 0..2 arrays with no element equal to any value at offset (-2,-1) (-1,1) or (0,-1) and new values introduced in order 0..2.

5, 11, 45, 173, 693, 2765, 11061, 44237, 176949, 707789, 2831157, 11324621, 45298485, 181193933, 724775733, 2899102925, 11596411701, 46385646797, 185542587189, 742170348749, 2968681394997, 11874725579981, 47498902319925

Offset: 1

Author

R. H. Hardin, Aug 28 2016

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 3 of A276299.

Formula

Empirical: a(n) = 4*a(n-1) + a(n-2) - 4*a(n-3) for n>4.

Conjectures from Colin Barker, Feb 05 2019: (Start)

G.f.: x*(5 - 9*x - 4*x^2 + 2*x^3) / ((1 - x)*(1 + x)*(1 - 4*x)).

a(n) = (8 + 27*4^n) / 40 for n>1 and even.

a(n) = (72 + 27*4^n) / 40 for n>1 and odd.

(End)