A275507 Number of 7 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.

48, 200, 1168, 7140, 43780, 268152, 1643372, 10069540, 61703488, 378096660, 2316847540, 14196847960, 86993404476, 533065762516, 3266444015616, 20015648328132, 122649024958372, 751551142797496, 4605247533843404

Offset: 1

Author

R. H. Hardin, Jul 30 2016

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 7 of A275504.

Formula

Empirical: a(n) = 3*a(n-1) + 18*a(n-2) + 11*a(n-3) - 23*a(n-4) - 4*a(n-5) for n>6.

Empirical g.f.: 4*x*(12 + 14*x - 74*x^2 - 123*x^3 + 60*x^4 + 59*x^5) / (1 - 3*x - 18*x^2 - 11*x^3 + 23*x^4 + 4*x^5). - Colin Barker, Feb 04 2019