A275506 Number of 6 X n 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,0) or (-1,-1) and new values introduced in order 0..2.

24, 104, 516, 2628, 13384, 68080, 346528, 1763408, 8974288, 45670736, 232422608, 1182818704, 6019467984, 30633598480, 155897059664, 793373760912, 4037548401360, 20547436657936, 104567700792400, 532154167518352

Offset: 1

Author

R. H. Hardin, Jul 30 2016

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 6 of A275504.

Formula

Empirical: a(n) = 3*a(n-1) + 10*a(n-2) + 4*a(n-3) - 4*a(n-4) for n>5.

Empirical g.f.: 4*x*(6 + 8*x - 9*x^2 - 14*x^3 + 5*x^4) / (1 - 3*x - 10*x^2 - 4*x^3 + 4*x^4). - Colin Barker, Feb 04 2019